Appreciate the feedback, you bring up some great points!
1. That's a weird new bug for sure. What was the unsure action you performed that caused the stamp to get stuck? Is this something you can reliably replicate?
2. That's not intentional, potentially a bug? Are you opening the mystery stamp packs every day (i.e. could this be related to transferring unopened stamp packs to the next day) or is it just preventing you from purchasing more than 2 per run regardless?
3. True, sounds like a good shop upgrade to me
4. Very much yes, variable earnings based on parcel size are in the works
5. Honestly, we didn't expect anyone to play long enough to notice the looping month, so thanks? This was a temporary solution to squeeze the calendar into the last update, congrats on revealing this dirty secret :D