Likely a bug. As I said, some units may experience this. If you will notice some other units as well, you can report this in bug report section.

But spirit bosses are supposed to be converted by using blood money on them and not be picked or is it a bug?

Some units can't be picked up when turned into gold. They should still be mine-able.

Regarding the lag, probably it happens when AI is switched to higher difficulty ( when inhibitor is destroyed ).

Btw, there's more up to date version of this map. It's Trick or Treat Halloween Editon. I suggest give that one a try, it should perform much better.

Good map but when attacking with many minions on enemy dungeon there is a great lag and dont know if it is a bug but when my imps take in prison enemy boss spirit and i use blood money on them they are converted immediately and i cant even pick them like they are titans

This is an updated version of Trick or Treat 1.0 public version.

This version has all mutator restrictions removed and brand new objectives. Also has very special AI system added. Contains narration, victory conditions and some terrain improvements.