In the past year I had three cartridge filters from the same manufacturer show significant media displacement upon removal, long before their service life had ended. The manufacturer sent them to a lab. I asked them to test the filter for efficiency. The lab used a Bubble Point test to check the integrity of the filter media. They sealed the filter on the top and bottom, connected pressurized air on one end and submerged it in oil. They applied 3" of water pressure and noted no bubbles and called it good. I have not found any information that this test could be used for an oil filter. Just a brief search on this test method, it can be used to calculate pore size of a filter, by increasing pressure until pubbles can be seen. I even sent them a new, unused filter, but they did not use it as a control. During the last six months they blamed me for damaging the filter when removing it from the cap. So I sent them a third filter still attached to the cap. They now speculate that I damaged the filter by inserting it in the cap. I sent them a Purolator filter of very similar design and media that I installed and removed several times and no damage to the filter. The manufacturer will not disclose the lab that conducted the test. Need this forum's experts to provide feedback on this test, the method they used. Attached are photos of the damaged filter and image of the test they performed. I will soon provide the full report but will not disclose the manufacturer at this time.