BangleJS 2: Garbage in filesystem

After a work out, i wanted to download the data but found garbage in the files system. Even though other data files had correct filenames, they contained a mixture of normal data and JS code.
Filenames look like this:

2 0- 4(!"D &0!$240h.dA`
20 0!"$!2T *!$(4 ""`ah

6 files whith those cyrted file names)

Trying to download this file does not finish, and backup procedure stops at this file:
666165,66,66 1648666167,65,5

Any suggestion how to avoid this?
(Firmware 2v14, Battery more than 50%)