'Child commit emitted before parent exists'

I just encountered this on a '-t 0' run with a fairly small repo (~500 files).

2021-03-26T17:11:38Z: Reading file list...done, 7682.755KB in 526 files (2.778sec)
2021-03-26T17:11:41Z: Analyzing masters...done, 3534 revisions (34.693sec)
2021-03-26T17:12:16Z: Make DAG branch heads...526 of 526(100%)    (0.000sec)
2021-03-26T17:12:16Z: Sorting...done  (0.000sec)
2021-03-26T17:12:16Z: Compute branch parent relationships...7 of 7(100%)    (0.000sec)
2021-03-26T17:12:16Z: Collate common branches...7 of 7(100%)    (0.049sec)
2021-03-26T17:12:16Z: Find tag locations...90 of 90(100%)    (0.032sec)
2021-03-26T17:12:16Z: Compute tail values...done  (0.000sec)
2021-03-26T17:12:16Z: Generating snapshots...done (38.973sec)   
2021-03-26T17:12:16Z: Generating snapshots...18
cvs-fast-export fatal: child commit emitted before parent exists

Unfortunately, I have a question regarding how to report further details since I'm unable to provide the proprietary repository. It's not lost on me how difficult it is to comment/help given this, but I am happy to work on any alternative suggestions we might explore so that we can unravel this.

For example, I've reviewed this in the debugger (breaking at the point of where the fatal error is output) and so far haven't been able to decipher what exactly is going on. I've also tried limiting the conversion to the single file seemingly identified as being processed when the error occurs, but this export works fine.

What else can I do to help with this?