I'm not sure this is a bug, but wanted to ask. Peeking at my save file, there was a Deep Ones mission that has a ridiculously long spawn timer. It originally spawned at start of March 2602, I don't remember doing the "wave 0" mission, which was evidently some time in mid to late April, but at start of May 2602, it is showing "nextWave=1", with a spawn countdown of 68 days (98910). Is that appropriate?
EDIT - sorry, legion, adding the data block for the mission:
If you need it, the current ID for ALIEN_MISSIONS to start this month was 349, so you can see it's an old mission, comparatively.