A boost leak will make the turbo spin faster than it should at a given amount of boost level. It is trying to compensate for the leak. Your gauge may be reading 25psi but in actuallity the turbo is moving enough air to make say 35 psi (depending on the leak, I’m just throwing out numbers here) on your gauge but you will never see that due to the leak somewhere between the compressor outlet and the throttle inlet.
When this happens you tend to do damage to the internal parts of the turbo (bearings, thrust bearing) this causes end play and damages the bearings from excessive heat. When this happens oil consumption begins. You are spitting oil out of the compressor side. This is generally only caused by a boost leak, compressor surge from a BOV not working at low throttle or boost situations (which I am more than willing to bet you have an 11psi spring in…that thing won’t open at low throttle or boost conditions causing compressor surge…kiss it goodbye) or damage from bearing wear due to lack of lubrication from the overheating of the oil…which causes in and out shaft play allowing oil to be forced past the seals and into your charge piping.
Another thing to consider too is if you have your breather vents back into your air intake that any blow by will be forced into the inlet of the compressor. When that happens you can start to build up oil over time. There is nothing that will correct this problem other than repairing any engine damage if the blow by is excessive.