there's absolutely no denying France (national team) is capricious, affected. But this isn't even worth posting about in bunches right now, it's well documented and has been discussed enormously in the past. They lose to Tonga in a RWC because they literally didn't want to play, even the Tongan players later admitted France seemed uninterested, with their minds elsewhere. I mean how else is a Tier 1 nation with a super scrum and excellent defense and good attacking etc...going to lose at the RWC, in the pools ?
Then you have your classic example, and I'll stop there, of France being able to beat the crap out of sides like few can, and then just lifting the foot off the clutch: 2006 FRA IRE. Look it up. 43-3 at a point, final score: 43-31. Read that line again. That's right.
So that's something you'll find some of in the Top 14, necessarily. I think Toulouse are the absolutely paradigm by excellence of that symptom: losing to Connacht at home, after beating the later H Cup finalists Saracens both at home and away. Losing to Munster by 100 points.
About the fact that clubs lose in away fixtures in the Top 14 very often, it's been discussed a lot previously. But obviously teams don't just feel hungover or lazy or wtvr when they play away; it's just the season's pace forces coaching staffs to be realistic and not burn their guys out. Not every team has the depth to play a legit B side on the road, and they most certainly can't have all their main guys start and play every single fixture. That's just not possible, physically, and therefor doesn't occur. Teams have to go into a foreign stadium with realistic expectations and targets: get a defensive bonus, maybe even tie. Perhaps try new/young player, strategy out...
But you're just not going to see Castres go into Toulouse and beat the crap out of them by 20, return home, beat Clermont and Paris, then play a couple of H Cup pool games against Leinster, then go to Montpellier and beat them, then play a close one in Toulon...like, haha, that shiit just isn't realistic.