anyone else have this problem?

[Archimedes]

I have my mussurana in a similar tank. she would do the same. What i finally did was grab some strips of Velcro, I really wanted mushroom lock but didn't feel like going out of my way. I flipped the back ground so the slots were at the top and velcro'd it to the glass, and made sure I had good bit of substrate against the bottom. Now I know, all over the place people say don't put tape in your snakes tank, so be aware of this. But i really didn't want to go the silicone route. I didn't want it to be permanent, and some times that stuff still stinks +24hrs later. She hasn't gotten back there since, but does give me dirty looks for stealing her favorite hiding spot. A BP may manage to still pry apart Velcro if they're able to get a good leverage on the slots up top.

To add to this, you can also get non-selfstick velcro, the kind without the adhesive backing, and glue it to the tank and to the styrofoam instead. a little more work and obviously the 24-hour cure time, but you can always access the back panel if you need to, and your snake won't get stuck to already-dried glue if he does manage to find his way there in the first place. Just don't use hot glue, as instant as the bond is, hot glue will melt the styrofoam and burn your finers when you try to press the glass-piece into its bonding position. But standard crazy glue would work fine, if you give it enough time to cure and ventilate before putting your snake back in. (Minimum of 24hours, to be safe. Those fumes are killer!)