[Trexmaster]

If you buy multiple Housekeepers at once, only one appears to recognize the buyer as the original buyer. The others bought will print the "Only the original buyer of this item can upgrade it." message when attempting to upgrade it, thus making upgrading the affected Housekeepers impossible.

In my case, I bought 3 Automatic Housekeepers, and only one will let me upgrade it, the other two printing the aforementioned message.

UPDATE: Relogging seems to have made the other housekeepers recognize me as the owner, and upgraded as normal.