indecipherable
漶 centers on something being unclear or impossible to make out, like writing that has become smeared or blurred beyond recognition.
漶 combines 氵 (water) with 患, likely suggesting water damage that makes something unclear or indecipherable. The exact historical development is uncertain.
Water 氵 pours over the right side 患, smearing ink and making the writing indecipherable.
For カン, imagine a can of water spilling over a document: can -> カン, and the water makes the text indecipherable.