Pulled the drain plugs today to change the fluid in the lower unit. Came out very milky. Last summer i did have some discoloration, I put new seals for the drain plugs in, also changed the water pump. I changed the fluid after a couple trips after changing the impeller, just to make sure i put it back together correctly. No problems. Thought i had it fixed. Now this.

Did i do something wrong? Something new going on? It is on a '95 merc 25 hp, serial #og157655.
Thanks in advance for any input.