Update: it seems to have happened again, but this time I noticed something. Both this incident and the last incident were preceded partially be a period of surveying a planet with life, with a companion by my side (Barrett, this time).

I may have even been on a surveying quest the first time, and a genetic sampling quest for the second.

So the common thread seems to be that this bug is somehow correlated with surveying a planet and/or combat involving alien wildlife.