And while I agree that itís more important to inspect a used filter, consistently new Fram filters that are pulled apart have a lot of internal rust and the cardboard end caps typically are not fastened well to the filter media and usually loose in spots and at one point used a cardboard anti-drain back valve who's sole purpose is to keep oil in the motor to avoid a dry start up which is when the vast majority of damage is done to an engine. Cheap cardboard has no place inside an engine.
I've never seen an anti-drainback valve hold oil for very long. Just lay a used filter on its side and watch the puddle form. I can't find the reference and can't tag the memory to source such as the SAE Journal which I used to read 30-odd years ago, but my understanding is contrary to popular opinion the purpose of the anti-drainback valve is not to retain oil but to keep the crud from being knocked out of the filter from a water-hammer like shockwave when the engine stops. Am dumbfounded if this is necessary then why is it in the filter and not the engine? Not all models of OE oil filters have the drainback valve, but most do. Has to be in the engine for cartridge filters.
Speaking of crud, the bypass valve is at the far end of the filter where big loose crud would accumulate. If it opens then oil which has passed over captured crud would carry anything loose back into the engine. That I have seen only AC/Delco filters have the bypass valve integrated in the drainback valve assembly at the open end of the filter.
I also like you have a 2016 Outback-and the filter mounting concerns me because the Subaru rattles-on start-up (theyall do)which is typical of a dry start & like you have found little oil when changing the filter although the Mobil1 1m-110 filters that iíve Been using lately seem to do a good job of keeping the filter full w/o leaking down. This is a big part of why I use the same filter on the fjr. And no cardboard. I may use a Wix next time, weíll see.
The Wix 57055 comes off dry just like the OE Subaru (OEM Fram) filter.
If it is desirable to retain oil in the filter then why not mount the filter open-end up? But throwing cold water on that theory was my 2000 Toyota Avalon and 2007 Toyota Prius with filters mounted at a 45į angle. When removed cold these filters had very little oil inside. The engines must siphon oil out as it cools. I thought that was great news for the Avalon as the oil filter was directly above a $700 active front motor mount and made an awful mess when half the contents spilled hot/warm. But only a drop or two spilled cold. And then I learned while a new filter and 5 quarts drained hot resulted in 1/8" to 1/4" over FULL the cold drain new filter 5 quarts was delightfully just under FULL. Get more old oil out cold than hot, no mess to clean up, perfect fill level, we have a winner! Cold oil changes from then on.
Cold changes didn't seem to matter much for the Prius. Just less mess or burned fingers removing the oil filter.
The filters on Toyotas held oil longer after engine turned off than my Subaru does.
2008 Ford F-250 Powerstroke 6.4L diesel uses a cartridge filter on top of the engine. Hot or cold seemed to have the same amount of oil after draining the crankcase: not very much. I used to a paper towel to wipe the inside of the cap and the cast aluminum cavity the filter fit into. Found same for 2009 Mercedes-Benz ML320 3.0L diesel. Current Ford F-150 2.7L EcoBoost has cartridge filter with tall plastic cap. About half the filter is in the plastic cap and half in engine casting. Is a long skinny thing. Haven't changed it yet but several YouTube videos show very little spillage removing that cap, it must not be full even hot.
Don't think my Subaru rattles on cold start but I can't say I've put my ear under the hood to listen. Can't hear it from inside. The whole thing rattles and shakes at idle, smooths out when moving.
Made a mess changing Subaru oil with a pan that was not long enough. Big drain hole, oil comes out fast, sideways, and splashes hitting the pan. Fumoto valve installed now.
The F-250 uses an M14-1.25 drain, Outback M16-1.50. The F-250 also made a mess the first time with huge volume of oil gushing straight out the bottom, 15 quarts. My first Fumoto valve. High enough in the air from then on I put about 6" vinyl hose on the Fumoto to reach an empty 1 gallon oil jug. Open the Fumoto, fill a gallon, close, repeat 3 more times. No catch pan to clean.
The F-150 2.7L has a huge bayonet plastic plug with an o-ring. All reports say this is another mess when huge volume of oil comes rushing out. Others say use a pencil or 3/8" socket extension to hold the plug partially in the drain hole to limit flow. I'll be finding out sometime soon. No Fumoto available but similar products are $80 for this engine. The OE plastic drain plug is $4.