Structure block activates excessively on redstone power level changes

Structure blocks perform their action every time the redstone signal strength they receive changes to a new nonzero value during the non-redstoning tick. This can cause excessive activations.

Steps to reproduce

1. Use a structure block to save a structure containing an entity (the entity allows checking that multiple activations occurred).

2. Set the structure block to load mode.

3. Build a comparator signal fade, and power it so that it is at a stable power level. The structure block will perform its action once, as expected. One entity will spawn, which can be removed.

4. Remove the power from the pulse fade. The power level should start decreasing. The structure block will perform its action every time the power level decreases, except when it decreases to zero. Multiple entities will be spawned.

Expected behaviour

The structure block activates like a normal consumer component, such as a dropper, and only performs its action on the rising edge of the signal. Nothing should happen when the signal changes strength but remains above zero.