You could ask the same question about any rifle and no I am not defending Tikkas I like alot of different rifles.
Sako, I had an issue with a broke butt plate on a 995, yes plastic. I also had a sako AIII 22 ppc that had a bad pipe on it.
rem 700 I had an issue with a blot one lug was out of wack and it dug out one side of the locking lugs, and cause major damage to the action in a 308. I had a wood stock swell and split on my because the wood was not dry, it was replaced
Savage I had one where the barrel came loose the lock failed.
CZ I had a spring break in the set trigger. sent back
Winchester, I bought a 22-250 with a bad crown on the barrel they had to re crown it.
I could likely go on, with shot guns to hand guns with broken bits and pieces I have owned and sold and traded many guns, and a few yes had some Issues.
You could pick apart any gun, and anyone is entitled there oppinion of them. The firearms I mentioned above were all great guns, but its like a car there are some good cars with bad designs and weak parts, Just Like Toyota makes a great truck and put crap tires on it, go figure...
I myself have not had an issue with the plactic bolt shroud likely only a matter of time until I do since i have 7 of the friggin things!