1. When placing a Creaking Heart which isn't surrounded by pale oak logs (and thus doesn't meet the requirements for spawning the Creaking mob) with /setblock the creaking blockstate will turn from "dormant" or "active" to "disabled" after about one second.

• /setblock ~2 ~1 ~ minecraft:creaking_heart[creaking=dormant]
• /setblock ~2 ~1 ~ minecraft:creaking_heart[creaking=active]

The following behavior which appeared in 24w40a seems to have been fixed (by 1.21.3), by automatically turning every Creaking Heart which fulfills the requirements for spawning a Creaking to "dormant". Thus, replacing it with a "disabled" one returns "Could not set the block".

2. When placing a Creaking Heart between two pale oak logs with /setblock, the creaking blockstate will immediately turn to "dormant" even if the command specifies "disabled"

• /fill ~2 ~ ~ ~2 ~2 ~ minecraft:pale_oak_log
• /setblock ~2 ~1 ~ minecraft:creaking_heart[creaking=disabled] replace