Bluetooth Heart Rate Monitor causing boot problems

Hey together,

Device info:
Device Type BANGLEJS
Firmware Version 2v13
Apps Installed boot, launch, setting, bthrm

{"id":"boot","version":"0.47","files":"boot.info,.boot0,.bootcde,bootupdate.js"},{"id":"launch","version":"0.13","files":"launch.info,launch.app.js,launch.settings.js","data":"launch.json"},{"id":"setting","version":"0.44","files":"setting.info,setting.app.js,setting.img","data":"setting.json"},{"id":"bthrm","version":"0.08","files":"bthrm.info,bthrm.app.js,bthrm.recorder.js,bthrm.0.boot.js,bthrm.img,bthrm.settings.js,bthrm.default.json"},"BANGLEJS","2v13",1652684710]

I've now erased everything, installed only boot, launch, setting and resetted, rewrote the settings and rebooted the watch. After that I connected the WebIDE, connected the app store and then only installed the BTHRM app. After reloading and starting the BTHRM app I get:

 2v13 (c) 2021 G.Williams
Uncaught Error: Function "setBTHRMPower" not found!
 at line 13 col 1 in .boot0
[ERASED]...
       ^
 at line 14 col 36 in bthrm.app.js
...ings.startWithHrm)){Bangle.setBTHRMPower(1,'bthrm');}
                              ^
> 

I've even tried to remove all files from the device storage from the WebIDE before reinstall.

Also tried everything with and without the "Pretokenise apps..." option.

Best regards