Hi @babydriver are you using the official build on the A5 ? There is an old OS related bug in the code. This issue should not be there on the test pie builds for the device. Plan to add the Pie builds to the official channel soon.
I bought this Samsung A5 very recently from someone who didn’t touch the original Samsung official OS (and the device still had the operator logo on startup) i didn’t checked what version of android was installed or if he did any updates.
But i remember that my previous (and sadly stolen) A5 had Oreo. Maybe it was the same for this one because i’m not sure that Samsung did the upgrade to Pie for this device
So I suggest you to first update your phone to the lats version (e-0.11-).
If it doesn’t solve the issue, I would install the stock ROM on the phone and re-install TWRP and /e/ after to be sure you have the latest baseband and stuff like that.
You can download the stock ROM here. There is a lot of HOWTO on the web to re-install the stock ROM for Samsung phones with Odin.