Board Game Arena

The passing action is an action like any other, so the player should have the ability to make conversions at the very end of the turn, i.e., after selecting the passing tile. Furthermore, if the "undo" is allowed for other actions, then it should be allowed for the pass action as well.

Here is the rule on conversions (page 13 of the BGA rule book):
"A Conversion is not considered your Turn action."
"On your turn, you may do any number of Conversions before or after your Action."

Here is a rule on the passing action itself (page 14 of the BGA rule book):
"When passing, immediately return your Bonus card and take one of the three available ones."

Note: the computer system automatically "immediately" returns your bonus card, and in the process of selecting one of the available bonus cards, I contend that the option to do conversions should be made available, as per the conversion rules.

Thank you for your interest and attention on this matter.

Yeah, that would really help sometimes.

I also found such unpleasant thing as no conversion offer after only digging and after building next to someone's single dwelling, which allows him to leech for free.

You can convert during any of those actions, just make sure to have the option selected where it asks for conversions at the end of all your turns selected.