Forsaken theories like what? That one came and compelled Elayne to hate Mat, Rand and company?

That sounds like a "fanboy" silly idea. Birgitte is her warder, and she knows compulsion. She would puzzle out what that feeling of ecstasy was, right away or if not the minute Elayne starts acting strangely...

We also know that such a Compulsion would cripple Elayne's character - as it can virtually never be removed (even Nynaeve failed - oh, she did remove the compulsion successfully, but the person died, as Rand knew would happen). Even Semirhage was most reluctant to do it, and we don't even know for sure if she did it right away or had decided to wait because she needed Elza to capture Rand). So what really are the odds that Jordan would have put a main cast player under that kind of crippling compulsion? Not good, IMO! Elayne is shown in at least one viewing to still be with Rand.

Compulsion has its limits too. Hatred for the Light or her friends would go so much against her deepest instincts such a compulsion might not even hold. It's also much more expedient for Graendal to capture Elayne and make her a pet if she wanted to cause "pain of heart" to Rand. She can only have learned from Moridin that Elayne is Rand's lover (Moghedien is the one who knows, and all signs point to the fact she's told Moridin, yet he made sure Cyndane wasn't told that bit).

If Moridin was ready to act toward Elayne at this point, the worst he could do to Rand would be to send Cyndane against her, and this would be rather obvious to him, that what would hurt Rand most would be to unleash Lanfear on his lover and the mother of his unborn babies. Compelling her to reject Rand sounds like a silly, lame alternative.