He has definately heard something but we don't know what as yet.
He said something like he should ask Rashi but she may not know anything. Yesterday when Urmila was talking to Sonal she did not at any point mention that Rashi had anything to do with anything Urmila had done. So even if Jigar had heard everything he wouldn't suspect Rashi straight away.
Jigar being a nice guy doesn't want to confront Urmila because he doesn't want to hurt her feelings. After all Jigar is a nice guy who has been brought up to respect hs elders. Urmila to all inttents and purposes is his mother now so he doesn't want to hurt her.
I'd like Jigar to stew for a while and keep thinking about what he heard. At the pandal I want to have him hearing more and more so he can form a bigger and better picture of what really happened.
Also I want Koki and Hetal to get a little suspicious. In today's episode they both mentioned that Jigar didn't look himself - if he walks around the house like this for a few more days Koki will definately realise there is something wrong.
Today for the first time he didn't hear what Rashi was moaning at him about, this bodes well in terms of Jigar thinking about what was said.
What we need as viewers is a flashback from Jigars point of view so at least we know what he heard.