J1939 TSC1 messages getting corrupted when concatenating files

[DM53204]

I have a datalogger that is capturing J1939 message traffic and saving MD4 files in 10-minute increments, about 10 MB in size each.

If am doing my post-processing using asammdfgui 8.8.13, the message traffic appears to be corrupted when I concatenate two or more files.

Example: In the raw, unprocessed log file, a message with the timestamp of 2026-02-28 20:25:27.870350 -06:00 has the following message header and data (this is the J1939 standard TSC1 message, being sent from a source address of 0x07 priority 3)

0x0C000007 C1 A0 41 FF FF FF FF 10

If I use asamdfgui 8.2.5dev5 to concatenate several files, the message is unchanged in the resulting concatenated file.

If I use asammdfgui 8.8.13, the message turns into this:
0x0002E5E9 FF FF FF FF FF FF E9 E5

Please advise. Thanks,

[DM53204]

I should mention that the corruption isn't with just the TSC1 message; there is other corruption, this was just an example.