Comparators do not receive signal strength from a shulker box fired out of a dispenser through a block unless it receives a block update.

I know it has a wordy title, but I can explain. Comparators are able to receive signal strength from a storage container through a solid block. As of 24w09a, Shulker Boxes that come out of Dispensers cannot give the aforementioned comparator any signal strength until the comparator receives a block update. This was not the case in any prior version.