this is usually a result when the teflon pin is worn on the bottom plate allowing a little flutter. This can be exaggerated with a slightly out of balance lead platter. I wrestled with this issue on my first maplenoll ariadne reference (white one with 40 lb platter) because of shipping damage and the worn pin. it is very difficult to find replacement parts for this so i ended up making a replacement. The platter balance is not as critical but for flawless performance is does help. I had the platter turned by a machine shop and balanced. Then repainted with a good grade of acrylic paint. The bottom pin can be pressed out and replaced but you must remove the plate using the three bolts. You can buy stock rods of teflon that will perfectly fit into the bottom plate then machine top so that it fits snug into the brass sleeve in the top airbearing plate. Carefully lube the brass sleeve with the supplied lube or high grade graphite grease. it sounds very difficult but its not really that tough if you are a little handy. I got pretty good at this while getting that table perfected. after that one, i moved up the the ariadne signature (beast of a table with a 90-100 lb platter). i currently own 3 maplelnolls including a heavily modified apollo that was the precursor to lloyd walker's current table. This one was modified by him and has an external drive vs the one attached to the plinth. the VTA adjustment is an engineering marvel.
Back to your other question. Yes on both accounts and yes on leveling the arm. Not sure about what model you have but i am a firm believer in getting base perfectly level. Usually the platter air bearing bottom plate is level, but if not, you will have a level base and the platter is slightly off. this can result in the platter bottoming out as it rotates and force higher pressure on the platter thus robbing vital air pressure to the arm. check them both. I spent a lot of time getting level right on platter. you will know you have it right when you spin by hand (with air on but belt not hooked up) and the platter spins for 3 or 4 minutes. You have not mentioned the arm so I am assuming its properly tuned and does not create a problem. If you level properly, provide clean, consistent pressure the the arm and platter, the maplenolls will produce some of the sweetest sound you will ever hear from a table in this price range.
Back to your other question. Yes on both accounts and yes on leveling the arm. Not sure about what model you have but i am a firm believer in getting base perfectly level. Usually the platter air bearing bottom plate is level, but if not, you will have a level base and the platter is slightly off. this can result in the platter bottoming out as it rotates and force higher pressure on the platter thus robbing vital air pressure to the arm. check them both. I spent a lot of time getting level right on platter. you will know you have it right when you spin by hand (with air on but belt not hooked up) and the platter spins for 3 or 4 minutes. You have not mentioned the arm so I am assuming its properly tuned and does not create a problem. If you level properly, provide clean, consistent pressure the the arm and platter, the maplenolls will produce some of the sweetest sound you will ever hear from a table in this price range.