I noticed the same thing last night, my bottle was getting low ( 150 psi )and the gas coverage seemed off. My bottle was filled at Praxair but was in outside storage at the local farm supply . I am not sure but it seems the 100 degree plus heat on that bottle in the summer and cool nights could possibly cause some condensate, Not really sure if that is possible or not with a full bottle.
The inline filter in my opinion is now a must for my gas bottle and will research into the materials i need and try to build one.
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