Return water temperature higher than output temperature

[filth]

Hi,

im running OTWG with an Elco Trigon 22 Boiler and a Siemens QAA73.
Opentherm Monitor tells me that return water temperature is 33°C, however i can see on the Siemens and in Opentherm monitor that the temperature of water leaving the boiler is less than the return temperature.
Flow temperature in Opentherm Monitor is what my Siemens calls "feed temperature" (Vorlauftemperatur in german) and its 29°C

I think there is something wrong - how can the return temperature be higher than the feed temperature?

[filth]

Boiler water temperature (id 25): 40.78
Flow temperature (id 31): 26.59
Return water temperature (id 28): 30.13

How can this be?

[mike7]

Flow temperature (id 31): 26.59

"31 R- Flow temperature CH2 f8.8 -40..127 Flow water temperature of the second central"

second unit ...