^Yes, Riker openly challenges Jellico in front of Troi. However, when Geordi approaches Riker about work difficulties, Riker also mouths off that Jellico has "Made it abundantly clear" he doesn't listen to him. That remark is out of line. It is a deliberate undermining of the Captain's authority. It is openly showing disapproval of a superior officer to your subordinates, which is a baulk at the chain of command, & passively suggests that his subordinates should do the same
Furthermore, when Jellico questions Riker about not changing the shift rotation, before Riker tries to explain, he gives a purposeful glance to Picard, long enough that Picard purposefully looks away & rightfully so. Though minor, that too is out of line. Your commanding officer is addressing you, & it's not Picard right now. It was a small infraction, but it set the tone right off the bat. Riker does not respect Jellico's authority. He made THAT clear right up front, as soon as the 1st order he disliked came down
Jellico's most objectionable statement was "I can see why he's still only a 1st officer". As offputting as that remark is, considering we know Riker's been offered 3 commands, it wasn't about Riker's qualifications or deservedness. It was specifically about his initiative. He made that comment directly after Riker failed to take the initiative to inform Jellico that one of his orders had been carried out successfully. Maybe that's not a big deal, but it might also be a symptom of Riker not being cooperative, & Jellico mistakes it for lack of initiative. Hell, Riker has questioned his own initiative before. So it isn't out of the realm of possibility that a savvy person like Jellico would take note of the man, & see some of his actions in that light. Incorrect about Riker? Maybe... Maybe not, but the reasoning he employed is sound enough
I mostly agree with all this, but remember there was a point in the show where Riker seemed to be onboard, "Well, I'll say this of him, he's sure of himself." but then....
Troi: "No, No he isn't!"
Also, re: mouthing off in front of Geordi...GEORDI was the one who suggested Riker do an end run and talk to Picard! I'm glad that didn't pan out. I'd hate to have seen Picard remind Riker this isn't the time or place for running to daddy to solve your problems.