Repeating command blocks set to always active will inexplicably stop running until replaced (broken and placed back or toggled from Needs Redstone and back again). This occurs when converting worlds from an older version (1.17 in this example) to a new version (1.18.1).

When converting new chunks (that aren't converted when the world first boots up), some repeating command blocks within 1-2 blocks of the +X +Z chunk border will stop updating. Only some command blocks are affected, other command blocks that fit this condition may not be affected.

(Seen in the image, red concrete represents the repeating command block below it has stopped updating)

What I expected to happen was...:

After converting, all repeating command blocks set to always active keep running.

What actually happened was...:
Some repeating command blocks nearing the chunk borders stop updating/running commands.

Steps to Reproduce:
1. Load the attached world save in the version 1.18.1. Note that it was previously version 1.17.1.

2. Run the command /tp 235.5 18 69.5 to teleport to an area with a field of repeating command blocks (which are supposed to place white concrete above them)

3. Press the nearby button, which will set all white concrete blocks to red concrete. Any red concrete remaining after this indicates that the command block below is bugged.

If necessary, two more testing sites can be found at by running /tp -500.5 18 69.5 and /tp -1000.5 18 69.5. White concrete near the player will automatically be turned to red concrete, so the area can be tested by flying next to the concrete and observing the same phenomenon described above.

Please try and fix this quickly, as maps which make frequent use of repeating command blocks may find it very tedious or impossible to update to 1.18 because of this.