Considering I only played an hour long game and took 3 planets within that time (all of them spawned marauders), that's pretty frequent.
Definitely, thanks for the info.
20 minutes between spawns seems like something is buggy with the timing.
Anyway, for 4.074:
* Marauders:
** Spawns now only happen when the marauder counter is "fully charged" (40 for diffs < 9, 80 otherwise) instead of having a random chance of triggering early.
** The counter is now capped at the "fully charged" level instead of 2x that, to avoid "stockpiling" resulting in multiple spawns over a short interval.
** The "number of marauders to spawn" was computed by roughly "number of human military ships here" minus "number of AI military ships here" (and capped at the value of the marauder counter). It now takes simply either "number of human military ships here" or "number of AI military ships here", whichever is larger (though capped at 4x the smaller value) and divides it by 8. This number is then doubled on normal unit caps, and quadrupled on low caps. Anyway, the upshot should be less chance of small marauder spawns that cause the marauder counter to stay "stockpiled".