Unfortunately this can and does happen sometimes due to contraction of the material over cold winters. Anywhere where there are openings or penetrations through the sheet flooring, this creates uneven stress points resulting in the material pulling away from itself. Cracks are often where there are floor vents...
Sheet flooring in an RV is stapled around the perimeter of the RV and is free floating. It can be replaced, but will never be same as done at the factory. It should not be glued down either. Much easier IMO is to install interlocking vinyl laminate planks. With laminate planks, it is VERY important to ensure that it is fully free-floating throughout and will not get hung up anywhere. There also needs to be an expansion gap all around the perimeter. It's so much easier dealing with one individual laminate plank at a time, rather than trying to wrestle a large piece of sheet flooring into place and then trim it and not make errors in cutting it.
If you wanted a cheap fix, you might be able to find a suitable size of sheet flooring under the bed storage, under a dinette seat or in a cabinet that you can cut a patch piece from. Then get a floor layer to seam weld the patch in where the crack is now. You could very well end up with this happening again tho.
On the bright side, this might be the chance to install a really nice looking laminate floor and transform the interior. Sometimes the vinyl flooring they use in RVs isn't exactly that appealing. I installed laminate planks in a previous TT and the original sheet flooring looked like a 70s kitchen remodel.