water can be in a trap arm if 1 its plugged 2 there is so much back fall that it fills up with water 3 there is a stoppage somewhere else. in addition specifically a plugged vent will not cause water to stand in a trap arm.
What you have going on isn't normal so there is a problem . I wouldn't say leave well enough alone . but some people can put up with more than others . And I don't trust water building up like that but depending on condition of property and owners pickiness wood floors or upscale house mold or water damage can come into play if its ignored. So its kind of an individual thing , I'd recommend getting to the bottom of it and being hands on will give you better understanding what's going on
Jeff, I appreciate your support with this issue. I am learning some things I didn't realize. As a side note, I can somewhat see in the trap arm with flashlight. Or rather yet, see thru it. I don't think it is full of water, just right up to the bend. Another thing I noticed tonight which explains the ticking noise, is every minute or so, a bubble forms. Which makes the echo in kitchen sink thru drain. Do I think there is a problem here? You bet. Has there been a host of knuckleheads in this house in the last last three years? Yes! Hurricane Harvey wrecked us with flood water. Then 2 years later, Tropical Storm Imelda flooded us again. Only about two feet of water each time but...so, tub was removed replaced with shower, new a.c. (yes there is another drain). Sinks and cabinetry pulled etc. PLumbing vent broken, I WILL GET TO THE BOTTOM OF IT! I am process eliminating, and my usual overthinking. I don't think I have a major problem. But I have a problem. I am a 57 year old female (not a cop out, just a disclosure) and I am pretty much going to tackle this myself since I did not get a call back from plumbing company. I think that is the 4th one that's a no show. I know this house literally inside and out, because of two floods. I would like to have a professional, but they need to be "on spot". It'll take me a few days to work this out, but I will come back and tell of my results. P.S. I think it's the plumbing ventI think there is crap down in it. Like roofing debris, pine needles, insulation, maybe a goblin. Or something those damn squirrels did.