Had a similar issue with our 2012 Cougar. The PEX drain line had worked loose where it is threaded into the bottom of the tank. I pulled the expanded foam from around the drain line so I could see where the line connected to the tank and then CAREFULLY tightened the line - then, after checking for leaks, resealed with the expanding foam. Be aware that it COULD be the fitting that is glued into the tank has cracked (possibly from being over tightened). Just be careful how much force you put on the line if you try to tighten it up.
Jack & Marty
2018 Laredo 298 SRL
2011 F-250 SB Crew Cab 4x4 6.7L