It cannot hit 260F with ethanol in there. If it tries, by being pressurized, the pressure will exceed its design rating and release (which may well be the issue you’re having).
if you haven’t already looked into: Bucket Tek (Cold Ethanol Extraction on a Budget)
then Reflux Still For Small-Scale ETOH Reproofing
Show me…
And go see Purging ethanol with hot plate