the first time I test this in my survival and then I test this in a creative world and was the same results

The villagers take and reject the professions until you trade with them if you make the next steps:

Steps to Reproduce:
1. put a villager on 4 walls of 3 blocks of tall but without the corners (like the image)
2. put a table of profession (smithing table (i never tried with other table))
3. when the village take the profession, just review the trades, don't trade!
4. go further than 7 or 8 chunks
5. return to the villager and destroy the table
6.place again the table, he will start taking and rejecting the profession

if you need more information comment this isue, please.