Problems that appear when importing pokemon

[Stymie]

HGSS - I imported Pokémon with the preferred hidden power and the move hidden power.  I tested them on the elite four and it worked, I saved before facing lance as I usually do and I beat him.  The end credit scene came on and completed, but then I got a file save corrupted message.  I showed up back before facing lance and beat him again.  I did it one more time and the same thing happened.  So I took a guess and used tms on the Pokémon with hidden power and I saved.  I beat him again and the game continued like it normally would.  Idk if this is a known problem, but I thought I'd mention it to help out.  I imported HP TMs and use them and did not get any problems afterwards.