First issue to report, basically just including this because the debug log entry says to:

Empire Mod - TaxTick - Catching Up - Did you skip time? Report this if you did not
UnityEngine.StackTraceUtility:ExtractStackTrace ()
Verse.Log:Message (string)
FactionColonies.FactionFC:TaxTick () (at D:/Games/Rimworld mod testing/Mods/Empire-1_6-Continued-main/1.5/Source/FactionColonies/settlements/FactionFC.cs:1476)
FactionColonies.FactionFC:WorldComponentTick () (at D:/Games/Rimworld mod testing/Mods/Empire-1_6-Continued-main/1.5/Source/FactionColonies/settlements/FactionFC.cs:511)
RimWorld.Planet.WorldComponentUtility:WorldComponentTick (RimWorld.Planet.World)
RimWorld.Planet.World:WorldTick ()
Verse.TickManager:DoSingleTick ()
Verse.TickManager:TickManagerUpdate ()
Verse.Game:UpdatePlay ()
Verse.Root_Play:Update ()

Second issue: I can't set my tax time interval to higher than 1 day. For some reason (this used to show up in the debug log as a yellow error, but I haven't seen/been able to find it for a couple of weeks while the issue's happening), every so often after setting a higher tax interval, the tax interval just force-defaults back to 1 day. I work around this by reducing the total silver gained per resource so the tax dumps aren't flooding me with silver, so it's not game-breaking. I unfortunately can't produce the exact error output for this, but I vaguely remember the log entry being something about the tax interval followed by it defaulting to 1.