Hi Jess,

Unfortunately it probably wont stop doing this, as the timber join is butted together that join will always move given the nature of timber.

A solution but might not be a cost effective solution would be to router the underneath of the join out with timber and glue in some more timber to help hold the join (a patch kinda thing) this will make the join stronger (assuming this hasn't already been done)

Then we only recommend either a oil or wax finish if you want it to be left with a natural look or we apply a clear epoxy resin finish, this is a very good product (about 2-3 mm thick) and it lets the timber move a little and the product moves with the timber rather than crack like the lacquer seems to do.

We pretty much always have the same result with kitchen benches when it comes to the sink area and joins.

The main cause I see happening is that the timber moves (and it will never stop moving) and then if the lacquer is not flexible it will split open causing a spot for moisture to get in and under the lacquer making it go all funky like that

A easier option would be to sand the tops and apply a oil and keep maintaining it, then you will never get the funky cloudy stuff happening, but you will need to do some research on what product are best and available where you are

Good luck :-)

Sand it back and then try Natural House Company - Osmo polyx hardwax. Only natural oil/wax product I found that would work in this situation.