Looks like it is some kind of conflict with brutalbosses - it refers to the Reaver
Remove brutalbosses or try other builds of these mods
Or check the config - maybe there is a way to disable the Reaver
If your block does not extend one of the blocks that supports canSurvive(), you need to do what they do with the updateShape() callback. It is called when neighbouring blocks change.
See for example, BushBlock, DoorBlock, TorchBlock, etc.
Or maybe FaillingBlock depending upon what you are trying to achieve?