Discolored exterior plastic conduit: heat damage?

Today I noticed typical 2” conduit with significant discoloration only on the two 90 degree elbows. The elbows feed almost directly into the main panel.

Is this heat damage? There is no water leaking onto this area and the coupling in this photo shows signs of some deformities, as if it has become malleable at time (no longer perfectly round).

Anyway, all I can think is that the SEC as damaged when being pulled through these elbows and now they’re overheating or arcing inside there. Service was installed in 2004.

Looks like an environmental issue that is discoloring the conduit not heat from within otherwise the entire elbow should be discolored.


Looks like UV exposure.

The. Conduit could have been a straight piece that was heated on site to make the bend and now the plastic is changing colors because of environmental things. Looks like couplers were used instead of the bell end of a factory made sweep.