Can you post some example filenames so I can see what you're talking about?
Of course, the first column is the filename after a rename using {year2}{month0}{day0}{hour24}{minute}{second}{seqn:-1,1} and the second column is the original filename out of camera:
0709081544231 original filename JU4H9180
0709081544491 original filename JU4H9181
0709081545081 original filename JU4H9182
0709081545151 original filename JU4H9183
0709081545171 original filename JU4H9184
07090815451711 original filename JU4H9185
0709081545231 original filename JU4H9186
0709081548351 original filename JU4H9203
0709081557101 original filename JU4H9233
0709081557131 original filename JU4H9234
07090815571311 original filename JU4H9235
0709081557221 original filename JU4H9236
07090815572211 original filename JU4H9237
0709081557431 original filename JU4H9238
0709081557501 original filename JU4H9239
0709081600571 original filename JU4H9240
0709081602531 original filename JU4H9248
As I see the last digit used from the seqn variable stayed allways the same=1. I dind't notus it, but nor do I understand the why now. Will try to check it somehow.