Thermal stats error R7800

A few days ago i installed the luci-app-statistics package on my R7800 (19.07.1). This works well apart from one thing.
When i open the thermal page it looks like two graphs are not displayed (only the place holders are visible). Also in the log 2 errors are shown:

Mon Feb 24 18:54:07 2020 daemon.err uhttpd[751]: ERROR: opening '/tmp/rrd/R7800/thermal-cooling_device0/temperature.rrd': No such file or directory
Mon Feb 24 18:54:07 2020 daemon.err uhttpd[751]: ERROR: opening '/tmp/rrd/R7800/thermal-cooling_device1/temperature.rrd': No such file or directory

I checked both the "....cooling_devicex" directories but the "temperature.rrd" files are not present. Instead the files "gauge.rrd" are present.

Should i simply rename these or is something wrong with some configuration?