filter cartridges, are very often designed to operate for filtration flow from
outside to inside. The presence of a support is quite always indication of the
flow (internal support = outside to inside flow, external support = inside to
It’s rare to find filter elements that have support on both sides. When the filter media inflates, or the filter cartridge "swollen" itself dilating to the side without support, we’d be in presence of extra flows (due to some circuit variation, even in fluid viscosity), or it’s easier that we’re facing some water hammers.
Water hammers are often symptoms of not properly filtered hydraulic circuits: particles flowing in fluid tend to block valve shuttles, this shuttles tend to remain blocked until the applied force to make them moving release them, at this point they move so rapidly that the result is a "water hammer" on the system. So, when you’re in presence of a swollen filter cartridge as the one visibile in this picture, take care to verify rapidly the fluid particle contamination.