Hmm, that reaction is interesting! I would expect it to not do that after drying.
I would think spraying over it with a lacquer finish is probably a good option. I have sprayed lacquer over hard finish oils, but never boiled linseed oil. Maybe experiment on a sample piece first.
100% boiled linseed oil will never completely dry. That is why I personally never recommend it. Once you put in on wood then it soaks into the wood a certain amount, so it would be extremely hard to remove all of it. There are products made with boiled linseed oil mixed with other ingredients that make good finishes that do dry to a hard finish though.
Personally I prefer polymerized tung oil. The word polymerized just means the tung oil was heated to a very specific temperature which helps the tung oil dry to a very hard and durable finish. I like the Sutherland Welles brand of polymerized tung oil because it is the best brand I have ever used. That brand is a tough finish made for wood floors.
Here is a good link about linseed oil and tung oil:
I am currently experimenting with some Minwax "Antique oil finish". It doesnt say anywhere on the can what this is based on, I suspect a polymerized oil as it dries quite hard in 24 hours or less. So far I like it for a low sheen finish, time will tell.
I sprayed some lacquer on a sample this AM, to test compatability, so far so good.
I removed the linseed oil by wiping it thoroughly with thinner and then I sanded it good. Sprayed laquer on and seems to be ok. However after a week or so on the spots where i burnt the position markings (with a soldering iron) the laquer seems to dissolve again. It gets sticky there. Is there some chemical reaction going on between the linseed residue and the carbon from the burned wood and the laquer? I was so glad that i finally got it right again with the laquer and it is a great sounding cbg!
Has to be the linseed oil causing the problem. You burned the markers with an iron which made a depression in the wood. When you wiped it down with thinner and sanded it down the sandpaper did not sand off the deeper depressions of the burn marks so some linseed oil was left in those areas.
Lightly burning wood with a wood burning iron will not cause finishing problems.