Well, you of all people should know how to put more than 64 frames in "one" animated tile :P I could also fake a path longer than 64 tiles by covering half of it with another layer (using 2 or 3 animations instead of twice as many)...provided there wasn't anything fancy behind it. Or by using the "Frames to wait between two animation cycles" option and crossing it with another path, though that's even more restrictive.

That aside, they aren't. The longest path is 32 tiles, in the version with hundreds there would probably be one nearing 64 but it would be really easy to stay within that limit. Maybe this screenshot will make it a little clearer:

(i swear this looks way better when it's moving and has the rest of the layers)
(i wanted to make it a gif but i'm pretty sure a good gif recorder is a thing that doesn't exist)