Cumulus Support

My weather station become a mad.
Records from the outside sensors looks resonable, but inside temperature graph looks like this:


Anybody has an idea what happens?
hardware: WH 1080
software: Cumulus v1.9.4 (1089)
http://zielona10.pl/trends.htm

Possibly a short circuit causing the reading to go high, intermittently. The reading looks as if it is going to the maximum limit for short periods before going back to normal.