That's a good point - I had my little test program constantly printing out, and that did indeeded freeze. I tweaked it to only print out every 10 passes through the loop, and sure enough that counter did continue to increment properly until it hit the next print, then it froze. So that does imply that it it continues to work and only locks up on output.

Quick edit mode was enabled, which I just shut off. I'll keep my fingers crossed that this was indeed the solution.