Data hiatus' from App

I record data from the mobile app while at home and inside my WLAN. The data are always there and are used to start and end charging every day. Going back in time the database seems to have recurring long hiatus’ though. What is going here?
Danke
Axel

With the help of KI I found out more. The hiatus’ begin when the RPi is crashes and/or ist restarted. Recording is resumed when I change something. The last change was adding signal strength as a new entity. Reading, using (in automations) and displaying the entities in short term history never suffers. It’s only the long term hsitory that is affected.
I use the last version of HA that runs on my RPi 3B.