I had my bunk boards replaced by a year ago. I went about 15 times and noticed this at one point is this a serious issue and needs to be replaced?

Like a lot of things, it depends. It looks like its just wood - no metal, poking through. Is your boat Fiberglass or aluminum? New or old? Is your boat a tool or a prized possession?

With an aluminum hull, even if it's your baby, your probably okay as long as there isn't a staple or screw head poking through. With fiberglass, you're probably still okay depending on your feelings. If it were my boat, I'd make a mental note to fix it but it wouldn't stop me from using the trailer.

Depending on where that spot is you may be able to add one of those trailer bunk slicks in that area. Those are a piece of plastic material that screws to the bunk, it may raise your boat off that wear spot. The slicks also help the boat slide on and off the trailer. Probably a temporary fix, but may give you a couple years depending on your boat. I had them on my old trailer and they worked well.

it's fiberglass and is my prized possession. It’s not just wood there’s no metal at all, and it’s a newer boat, a 2020 model.

I changed mine to Gator Backs a couple years ago. They have been alot better than all the boats I've had with carpet bunks.

I would check the positioning of the bunk in question. My bunks have been on for 10 years and I don’t have any carpet rips or exposed wood. The last time I changed them I left the brackets that attach to the boards loose and loaded the boat. Then crawled underneath and tightened them up. I’ve had to re-snug them a couple of times.

The issue with leaving it exposed like that is that the wood will rot and then become weak.

I would address it with new bunk carpet or gatorbaks like @Siebert Outdoors posted. I've been considering going to those myself. I've replaced my bunk carpet twice in 10 years now.

I agree I will look into that do you think it will hurt the gel coat on the boat atm

Over time the wood might scratch the gel coat. If it were mine I’d either recarpet that skid or have whoever did the work replace it.