The CC log files are stored in an app-private folder that the T68 should ignore. Clearly it doesn't.
Another user had a similar problem on a C67ML.
That discussion didn't go well. He ended up writing a 1-star review on Google Play in effect accusing me of fraud and threatening to "report" me somewhere for selling an app that was "not fit for purpose" and violating some consumer protection law.
That said, the advice given to him is still correct -- tell the device either to ignore folders or look only in specific folders, whichever option it supports. The docs for his device say that there is an option to scan only the "Books" folder. If you have that option then set it, and tell CC to put books there. The problem should be solved.
I avoid this problem (actually never saw this problem) on my Onyx Afterglow2 and Energi Systems Pro (a Boyue T62 clone) by not using the built-in book manager. I installed Nova as the desktop, use CC as the library manager, and use Moon+ as the reader app. CC can see the built-in FBReader app but I don't like it so don't use it.