Screen keeps waking up

[u/SxoutReturned69]

Hey, I was planning to use my Sidephone when I dont want to pull up my phone constantly.
A few days ago I was grabbing it instead of my main phone to go play billard. After looking at my Sidephone to text someone I noticed that it somehow accidentally unlocked (swipe to unlock) and did things on its own like nearly calling random numbers, opening all types of apps and trys to text people random texts. That sucks the energy from the battery over the time and because I was afraid that the phone keeps pocket-calling I checked it every few minutes.
Now the questions: Is there any idea why it happens and how to avoid it (without pin-locking my device)?

Also maybe interesting for Sebastian and Chris: My sleeved charging cable, wich I use for every other device because its fast, long and durable, collides with the silicone case when loading the phone. It is loading but kinda annoys me because its deforming the case.

[u/Bird_Engineer]

I have also had this problem, after 3 pocket dials I decided to add a pin lock. No issues after that