First of all: I'm very proud of Mojang for noticing the invalid "uv" values for flower pots' bottom texture missing, it's not missing anymore, however only if the pot is empty, else if you place anything in it be it flower, sapling, cactus, dead bush, mushroom, the bottom texture disappears again.
Thank you for your report!
We're actually already tracking this issue in MC-170842, so I resolved and linked this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature in the future to see if the issue has already been reported.
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