Two thoughts.
1. Never put tape, or anything sticky in your enclosures. This can hurt your animals. If you want to secure a probe, drill another small hole or two and secure with a plastic zip tie.
2. If I can see it correctly, the probe is below the shelf? Maybe you can put it closer to the RHP and above the shelf and just adjust temp accordingly? In my boaphile tank for my carpet python, where the higher perch is further back and closer to the RHP, I keep the probe at the same height and do have to keep a closer on eye on that tank then other tanks as room temp changes. This is just a thought and I am not clear on how the shelf can impact things as I've never had one.
As I mentioned in #1, securing the probe with a zip tie might help keep it against the wall of the tank and above the shelf.
Keep us in the loop and good luck.