After a PM with a moderator, he suggested to post my issue here.
I'm playing Faery/Rogue and we're in the middle of war. We were waiting for a UD armies to get back in (his first army got back at 10:31 - army #2 at 10:51 and army #3 at 10:52). Army #1 consisted of around 5k elites and army #2 and #3 had around 7k more elites for a total of around 12k elites home.
I went and propaganda on him at 10:54 (avoid slight delay of troops comming home) and was getting any other troops easily (wizzies, thieves, specs, sols) but everytime id land an Elite prop, it would tell me that unfortunatly, no elite could be converted.
While i know there is a random factor to prop, I cannot believe it can happen 4x in a row and only for elites. Sounds fishy to me.
And yes, his armies were home (and we were 3 to check that he wasnt online and didnt do anything with his troops home).