Is there anything I should know when using the LCDC interrupt ?

There is one Int $48 signal. When this signal goes from "off" to "on" the LCDC flag in the register IF ($ff0f) gets set, and ONLY on off-to-on transitions.

If the signal is already "on", say by a true (and enabled) LYC=LY condition, then a further interrupt in the same line (say HBLANK int is enabled as well) would set the int48 signal as well, but it's already set so no off-to-on transition, no further interrupt generated.

But the HBLANK interrupt could occur if LYC=LY would get disabled or false (lyc changed) within the line, ie. if int48 signal gets off for a short moment. (Info from M.K.)