Protests draw attention to your cause. This doesn't draw attention to anything, it is straightforward sabotage. Neither is it in line with how typical protestors operated before.
You are jumping to the assumption that foreign agents wouldn't be exposed, but any willing idiot can be bought to conduct such activity. Recent research in Denmark showed that sabotage comes, most likely, from locals, persuaded by foreign actors.
So two things could be true at once. A local 'protestor', disengaged through some issue (whether climate, farming or anything else), persuaded to join some 'resistance' by anyone.
I don't expect this to be supported by local protesting groups, like FDF or XR, either. Way too risky, media-wise.
It could also be kids doing it "for the lolz", like in slovenia:
https://www.rtvslo.si/crna-kronika/na-zelezniski-progi-iz-ce...
similar thing happened next to a minority area where they put railroad ties (the big wooden things, usually supporting the tracks) on the tracks themselves, and well, that even got politicized for the location reasons.