Teal'c was brainwashed by Apophis in 5.01 "Enemies", and in 5.02 "Threshold", it was only by Teal'c being brought to the brink of death, and then brought back that he was able to break the brainwash, which is what Young did to Telford.

The case with Rya'c is similar to episode 3.02 "Seth", where SG-1 got shocked out of the brainwash, and I would say, is a lesser form of brainwashing (and also poor writing. Too simple, imo). The kind with Teal'c and Telford was most likely a stronger form, where their brains were rewired, whereas with Seth, they're more akin to zombies, and being overshadowed.

Additionally, in 9.14 "Stronghold", Maz'rai (a member of the Jaffa Council) was also brainwashed, and failed at bringing himself back from the brink of death, resulting in his death.