For those starting Yerushalmi Makkos (just over 4+ months till the cycle is done!):
1) R' Yochanan (1b) interestingly holds that if eidin zomimim are mechayeiv mamon and malkos in one act of testimony and are huzam they both pay and get malkos. The Mareh haPanim already alludes to the fact that this may be the singular example of a case of double jeopardy. I figured I would impress my son with this bekiyus yediya, but he has reached the point where he always one-ups me. R' Meir holds that eidim zomimin always get 40 extra lashes for violating "lo ta'aneh b're'acha eid sheker" in addition to the 40 lashes for "ka'asher zamam" or having to pay because of "ka'asher zamam". Rashi explains that according to R' Meir this is not double jeopardy because there are two separate issurim involved: 1) lo ta'aneh 2) ka'asher zamam. However, if the same testimony were mechayeiv mamon and malkos (e.g. motzi shem ra must pay and fine and gets malkos), R' Meir would hold there could only be one punishment because the rule of no double jeopardy still applies. Tosfos (Kesubos 32b d"h shelo) disagrees and argues that certainly in a case of motzi shem ra where the eidim attempted to be mechayeiv mamon and malkos they would get both in return. My son pointed out that R' Yochanan's chiddush seems to be the very point of debate between Rashi and Tosfos.
2) The Bavli (Kesubos 33a) struggles to come up with a reason that eidim zomimim do not need hasra'ah and finally concludes that this is a function of ka'asher zamam: they triwed to inflict punishment of an innocent person without warning, therefore they deserve no warning. The Yerushalmi (k'darko) cuts to the chase and is far more practical (4a): eidim zomimim get not hasra'ah because we see anyway that people know the consequences of lying under oath (they see other eidim get punished) and they do it all the time anyway.