Only half of my Piloswines evolved.

[Zulkir]

I leveled a swinub to 98 and evolved it into a piloswine at 99. Then I grabbed a test swinub and evolved it at 33. I then taught them both ancientpower at the move tutor and leveled the test 'swine to see if the evolution actually worked. It did and I proceeded to level my other piloswine to 100 to evolve it.

 

The piloswine I actually wanted to use leveled to 100 and failed to evolve. Can anything be done about this? Is it because I used a rare candy to level it and the game is coded to only check the moveset for the conditions at the end of the battle? Is it another issue entirely?

 

Thanks in advance for any response.