You are expecting to much from the seal coat---
What you are describing is quite normal---the first coat always is un even--it's wood and some places absorb faster than others---
If it's not to full of dust and such--add another coat---after it's dry run a buffer with a fine screen over the entire thing--this will remove the dust and crud that always roughens the first coats--
then vacuum--and wipe--then add your final coat.
I'm not a pro finisher--there are a few here---so if and when they check in--you will get more clear instructions---Mike-----
What you are describing is quite normal---the first coat always is un even--it's wood and some places absorb faster than others---
If it's not to full of dust and such--add another coat---after it's dry run a buffer with a fine screen over the entire thing--this will remove the dust and crud that always roughens the first coats--
then vacuum--and wipe--then add your final coat.
I'm not a pro finisher--there are a few here---so if and when they check in--you will get more clear instructions---Mike-----