We had the same problem with our 3670 last summer. The roller under the fridge would push a bubble under the vinyl each time we brought that slide in. I thought we solved the problem by putting a flat piece of heat duct tin in front of the roller to spread out some of the weight from the roller. All that did was lift the corners on each side of the tin next to the rollers and it got all bent up and jammed under the slide. My hands didn't appreciate the cuts from that great idea.
We finally thought we had the problem licked when we found some thick (1/8"), stiff cardboard to put under the roller. Seemed to do the job well as there was very little bubble in front of the rollers path as I peeked underneath the cardboard while my wife retracted the slide. The problem returned this spring when I went out to get the unit ready for it's first trip.
I found that the vinyl had snapped apart from the right side of the roller, under the slide, to the heat vent located to the right. I figure it was due to the extreme cold (mid -30's C) on that stressed piece of vinyl. I also found when I lifted the vinyl that there was no adhesive anywhere but on the edge that would have been under the oak kick facing of the slide. The only signs of adhesive were found along the edge of the vinyl, along with holes like a stapler would make.
Further research to try and find a fix showed that many manufacturers use this method of stapling a glued edge as standard installation procedure for laying a vinyl floor. It also showed that some manufacturers are also aware of this potential problem to units sold in a cold climate by giving you the option of gluing the entire floor for an additional cost. I bought used, so I got it filed upstairs if I ever buy new.
I eventually lifted both pieces as far as I could without causing more damage and applied a quality adhesive and then rolled it. I could not get the 2 pieces tightly back together and camped with a 1/8" -3/16" gap this year but the bubble has not returned. I also bought a small mat to throw over the unsightly gap and have promised my wife a new laminate floor for it next year.
Maybe try something stiffer like that 1/8" paneling to buy you some time and minimize the stress , but get that vinyl fastened as fast as possible because that flexing is not good. And if you get cold in your area, do it sooner.