A compressed load - normal.
Just remember that your ought to scrape it out and start over. Your loads need to be compressed with BP. If for some reason you decided to pull the slugs, lube them and then re-seat them - a variation in seating depth could leave an air space.
Chalk it up to "experience" - we've all made mistakes at times - just be on the save side and "start over" - the cardinal rule in reloading when you've messed up.
As as a side note - when I first started reloading BP cartridges, I loaded several and then pulled the slug to check that I was getting a good compressed load. It's a bear trying to get a compressed load out of a casing at times.
I don't know how many you have but to make short work of it, you may want to pull the slugs and just fire them off afterwards - de-prime, wash your casings, dry and start over. NOTE: If you do decide to pull the slugs and just fire them off - load ONE AT A TIME in your revolver - otherwise, you'll likely experience a "CHAIN FIRE'' - WHICH YOU DO NOT WANT! PUT ONE IN THE CYLINDER AT A TIME. I know . . . the cost of primers and the powder . . . but it's a whole lot easier than "doing it by hand". Sometimes the "lessons" cost a little but the learning experience pays off in the end.
For my 38 special BP - I usually use a 160ish gr RN from a ideal/Lyman 358-311 mold. I finger lube mine - then swipe the base across a piece of paper towel - then seat. I seat right on top of the powder - don't use a wad. I've never had a problem with any of the lube migrating down to the powder. Any excess lube is pushed up by the case mouth when seating. Yea, it can be a little messy but that's why I have a dedicated set of dies for BP cartridges. After a loading session, I clean them well as the seating die is the one that gets the most "gunked" up. Some like to use a wad or card between the powder and slug - all depends on what you like and how you prefer to load.