If an accumulator (multi-block version, but testing was done with only a single block) is made to be part of a contraption, and is then disassembled to no longer be a contraption, it no longer takes in, or outputs FE properly. Example for recreation is to put an accumulator on top of a cart assembler, power it on, let it be picked up by a cart, then power off the cart assembler to drop it back off. Giving a redstone pulse to the accumulator after it has been dropped off and disassembled allows the accumulator to take in FE properly again for some reason, however it still does not output power. Breaking the cart assembler fixes the problem entirely and allows it to both take in and output power as normal.

EDIT: After further testing, it seems like if a larger accumulator (2+ accumulator blocks) is glued together and used following the same procedure, only the block that is directly attached to whatever caused it to become a contraption (cart assembler, gantry carriage, etc) does not work properly. All other blocks in the multi-block structure seem to work properly.

Additional context

• MC Version: 1.18.2
• Mod version: 20230221a (latest as of writing this)
• Forge version: 40.2.0
• Create version: v0.5.0i (latest as of writing this)

Fixed in 20230309a.