I think this issue is still there.

Thx. I got it wrong.

Maybe you miss out the following description:

choosing a single number and moving it some number of positions to the left.

You can't move number to the right.

Your example is too long, I tried your solution and found a way shorter example.
Given a = [3, 2, 1] and b = [2, 1, 3]. Your solution returns 1, but obviously the correct answer is 2.

For instance, these two arrays:
a = [323, 160, 477, 470, 471, 436, 105, 136, 253, 248, 109, 259, 463, 488, 297, 421, 293, 180, 276, 388, 75, 345, 358, 79, 372, 373, 37, 90, 152, 389, 486, 387, 439, 77, 497, 44, 357, 148, 189, 498, 70, 250, 296, 121, 489, 400, 464, 351, 155, 426, 191, 257, 269, 80, 244, 278, 29, 161, 198, 476, 419, 335, 183, 149, 122, 294, 34, 242, 313, 102, 89, 59, 429, 144, 135, 433, 336, 328, 206, 13, 182, 212, 41, 128, 103, 87, 370, 71, 48, 172, 139, 431, 234, 61, 137, 309, 200, 413, 246, 320, 66, 11, 462, 273, 21, 2, 342, 188, 332, 58, 314, 165, 280, 344, 134, 167, 49, 460, 228, 495, 169, 281, 322, 72, 190, 158, 316, 106, 260, 288, 284, 241, 138, 292, 60, 443, 386, 299, 334, 467, 418, 179, 490, 303, 348, 97, 496, 40, 318, 207, 209, 52, 484, 120, 145, 361, 319, 219, 104, 157, 5, 325, 222, 417, 304, 442, 181, 78, 65, 68, 331, 133, 229, 450, 125, 290, 405, 245, 454, 363, 47, 35, 25, 254, 430, 472, 324, 256, 42, 291, 369, 140, 159, 92, 263, 397, 177, 194, 132, 45, 449, 33, 184, 225, 93, 475, 249, 205, 452, 438, 56, 86, 15, 367, 311, 482, 265, 46, 116, 108, 107, 131, 162, 82, 32, 51, 410, 465, 83, 378, 266, 399, 339, 483, 434, 368, 186, 402, 377, 289, 326, 143, 412, 337, 287, 201, 407, 111, 445, 31, 166, 17, 171, 374, 385, 20, 428, 214, 98, 283, 315, 10, 14, 84, 398, 308, 175, 192, 99, 453, 54, 147, 473, 251, 88, 298, 302, 415, 481, 243, 12, 233, 235, 220, 275, 110, 424, 359, 440, 435, 437, 238, 468, 193, 141, 239, 223, 118, 62, 271, 285, 392, 279, 383, 493, 73, 94, 447, 4, 362, 176, 154, 164, 216, 353, 395, 23, 330, 277, 282, 213, 466, 403, 340, 307, 310, 352, 211, 126, 204, 1, 264, 346, 456, 329, 355, 7, 270, 187, 237, 381, 360, 16, 170, 404, 350, 117, 341, 401, 142, 91, 422, 113, 391, 317, 173, 3, 210, 327, 338, 494, 28, 185, 255, 153, 203, 36, 168, 39, 146, 130, 9, 57, 356, 305, 365, 487, 115, 448, 218, 408, 380, 457, 343, 425, 217, 485, 444, 50, 202, 227, 416, 163, 394, 43, 151, 26, 406, 384, 492, 6, 226, 150, 306, 321, 236, 224, 195, 379, 272, 215, 258, 67, 199, 333, 197, 114, 375, 349, 364, 22, 18, 390, 38, 420, 8, 74, 499, 295, 409, 123, 30, 85, 53, 64, 459, 432, 300, 376, 455, 63, 81, 119, 469, 221, 19, 366, 411, 441, 156, 100, 76, 261, 423, 230, 55, 232, 208, 312, 491, 446, 262, 178, 382, 124, 301, 24, 231, 414, 127, 458, 101, 267, 474, 451, 240, 354, 479, 252, 286, 371, 427, 129, 274, 196, 500, 268, 112, 393, 461, 347, 478, 69, 96, 174, 247, 480, 95, 396, 27]

b = [318, 497, 77, 177, 35, 58, 92, 347, 185, 164, 406, 337, 136, 105, 480, 175, 426, 68, 271, 140, 27, 147, 458, 371, 304, 202, 176, 469, 218, 325, 411, 432, 456, 67, 100, 450, 130, 103, 60, 228, 322, 169, 340, 448, 101, 328, 281, 163, 490, 311, 370, 489, 300, 439, 25, 7, 10, 148, 435, 76, 386, 459, 317, 390, 124, 321, 102, 69, 85, 226, 494, 383, 326, 420, 306, 482, 361, 151, 305, 9, 2, 44, 310, 465, 41, 50, 493, 466, 299, 135, 495, 380, 32, 89, 499, 172, 316, 170, 372, 62, 363, 332, 395, 237, 424, 479, 149, 29, 249, 242, 399, 266, 128, 421, 391, 412, 384, 488, 473, 8, 368, 183, 455, 396, 112, 433, 227, 122, 111, 314, 413, 72, 353, 366, 61, 288, 264, 374, 178, 11, 403, 93, 341, 481, 234, 296, 84, 205, 431, 356, 334, 247, 339, 198, 194, 20, 409, 291, 131, 96, 369, 295, 437, 487, 389, 354, 484, 483, 187, 330, 53, 208, 119, 440, 141, 258, 430, 99, 17, 429, 193, 132, 59, 467, 80, 313, 87, 294, 46, 241, 358, 398, 364, 315, 167, 292, 416, 323, 203, 142, 4, 320, 114, 265, 276, 81, 123, 283, 195, 3, 109, 453, 229, 452, 379, 460, 232, 63, 468, 392, 290, 273, 268, 293, 367, 402, 329, 14, 463, 447, 243, 64, 220, 425, 154, 275, 255, 75, 477, 298, 308, 55, 204, 333, 250, 246, 382, 397, 12, 189, 327, 231, 454, 417, 285, 120, 219, 470, 272, 171, 115, 352, 200, 262, 301, 445, 133, 104, 277, 197, 39, 336, 418, 400, 259, 88, 94, 475, 287, 348, 108, 74, 1, 214, 449, 23, 90, 256, 343, 56, 408, 38, 303, 110, 37, 355, 307, 446, 224, 240, 373, 434, 107, 65, 165, 474, 33, 442, 207, 385, 491, 346, 213, 284, 211, 152, 267, 331, 118, 419, 127, 190, 150, 225, 173, 209, 280, 116, 21, 253, 196, 48, 282, 410, 137, 257, 436, 464, 404, 156, 261, 98, 206, 393, 144, 423, 52, 30, 34, 251, 191, 381, 235, 143, 233, 451, 174, 286, 478, 486, 362, 365, 496, 49, 155, 335, 45, 184, 95, 360, 179, 138, 86, 344, 106, 492, 113, 388, 312, 415, 180, 26, 166, 338, 192, 57, 461, 16, 54, 405, 216, 230, 443, 394, 66, 457, 79, 42, 97, 145, 309, 43, 244, 28, 153, 377, 70, 349, 78, 139, 125, 188, 239, 212, 36, 238, 83, 126, 18, 160, 159, 289, 157, 222, 279, 31, 51, 223, 444, 342, 302, 422, 350, 146, 5, 414, 485, 186, 91, 181, 357, 378, 254, 210, 236, 215, 162, 82, 263, 182, 161, 269, 345, 438, 472, 24, 407, 471, 476, 199, 498, 278, 260, 401, 221, 319, 462, 73, 375, 201, 427, 13, 117, 324, 40, 297, 168, 245, 217, 19, 351, 6, 134, 121, 441, 252, 22, 158, 274, 376, 428, 387, 500, 71, 47, 15, 248, 270, 359, 129]

They have a common subsequence:[105, 439, 148, 102, 89, 172, 332, 314, 72, 288, 334, 484, 430, 132, 452, 367, 402, 14, 243, 220, 275, 285, 94, 23, 213, 211, 381, 360, 113, 338, 28, 153, 36, 146, 485, 236, 215, 199, 375, 19, 441, 252, 274, 500]. len(a) == len(b) == 500 And, the common subsequence's length is 44, not 6.

So the answer cannot be 494(which the python version says), should be no more than 456.
Maybe you should check it out.

Approved, thanks!

Fork to this behaviour: https://www.codewars.com/kumite/62a741d0776e870064aac0ed?sel=62a741d0776e870064aac0ed

You should add what is the range of all A[i] and B[j].
In particular when they are numbered from 1 to N.
More especially when the original kata page gives more information than you.

This kata is Python only at the moment I'm writing.
Given some users already found the correct solution, there is an issue in your solution, not in referee solution.

Maybe there's something wrong with the python translation ?
For every random test, a longer increasing sequence can be found than the answer.

Fixes It(desc, closure()) closure() variable capture which made the can solve 6x6 puzzle tests repeat the same test three or four times.

Why? Design an example which this code will fail.