Present in 0.6.3:  

1) Pregnancy penalties can go into effect multiple times, and are not properly removed when the pregnancy ends.  After playing around a bit, I believe it is due to an interaction with the save/load system.  If you save a game with a visibly pregnant character, when you reload, the pregnancy icon is not present.  It only appears when you advance the time, and when it does it re-applies the penalty.  

2) Allowing the wedding crashers to sleep with your spouse costs you 5000 gold, rather than giving you 5000 gold.

3) The game only seems to give the Heir Education option if the *mother* (not the child) has the Heir type.  

4) [Might be a bug, or intended behavior]  Children only get the Heir type if they are *conceived* between the Master and their spouse.  That is, if the Master/spouse is already pregnant when they get married, but have the child after the wedding, the child will not be an Heir.

Also present in 0.6.4:  

If two incompatible races have sex (and neither has the breeder trait), the text  says "[name] could get pregnant from it".  After a bit of digging, I think the issue is in globals.gd: 

if mother.has_status('breeder') or father.has_status('breeder'):
    result.value = true
    result.compatible = true
else:
    result.value = false
    result.breeder = false

That last line should probably be "result.compatible = false".  

(The fact that "value" is false means that the pregnancy doesn't actually occur--it's just that the wrong message is generated.)

The servant that you get in the beginning cannot preform any task unless it's in a dungeon. You can tell them for upgrade for instance, but no progress will be made.