Kegged beer decarbonating initially after tapping
New to this forum, so firstly, hello!
I was wondering if this community could help me out with a weird problem. I have been brewing and kegging at home now for quite some time, and more recently (past 3/4/5 batches), when I tap a new, freshly kegged & carbed beer, the pours are completely decarbonated. It looks just like it did after I transferred from the fermenter. Zero fizz whatsoever.
The first time it happened, I opened up the keg lid and everything looked fine. I actually poured back the uncarbed beer back into it so as not to waste it in case I could fix the beer, and noticed that when I poured it into the keg the beer all foamed up. This indicates that the beer itself is actually carbonated, but it is during the pouring process from keg to glass that carbonation is somehow lost.
I took out the dispensing post and draw straw and cleaned it out, noticing there was some dry hop matter transferred from the fermenter during kegging (unintended but it happens, right). I assembled it and poured, and still nothing. I repeated the cleaning process again, and low and behold, a bubbly beer with a perfect head emerged!
No big deal- must have been a dumb coincidence. However, the problem persisted for all batches (several) since! The freaky part is that the fix always require exactly two separate draw straw cleanings, and a lot of the time I don't even notice any hop matter stuck in it.
Luckily I have no lost any beer to this, but you can imagine that it's not practical and shouldn't be necessary to go through this process (that doesn't even seem to make sense) every single time. The worst part is, I have made kegs in the past where there are no carb problems at all and it comes out perfect first try. It has only been recently where this has started to happen.
I do a good job cleaning the keg components regularly and am pretty careful with limiting sediment/solids transfer from fermenter to keg, so I wonder how I've gone wrong in my process? This has happened on two kegs separately.
Has this happened to anyone else? Is there a long term, permanent fix? Does anyone know why this is even happening? The whole thing seems unscientific, lol.
Thanks so much in advance for your help!