Severe tick slowdown in command-heavy worlds after updating to Bedrock 26.51

After updating Minecraft Bedrock Edition to version 26.51, an existing command-heavy world became extremely slow.

Before the update, the same world and the same commands worked normally. The severe slowdown started immediately after updating to 26.51.

The world contains more than 100 repeating command blocks that run commands every tick. The commands mainly use /execute, /scoreboard, /tag, and entity selectors such as @e.

Steps to Reproduce:

1. Open a world containing many repeating command blocks.

2. Run many /execute, /scoreboard, and /tag commands continuously every tick.

3. Observe entity/player movement, block interactions, redstone, and command execution.

4. Disable all of the repeating command blocks.

5. Enable the command blocks again.

Expected Result:
The commands should run at normal game tick speed, similar to how the same world worked before updating to 26.51.

Actual Result:
When the commands are enabled, the tick speed becomes extremely slow. Entity and player movement is delayed, block breaking and placing is delayed, and redstone and command execution become very slow.

When all command blocks are disabled, the world immediately returns to normal performance. When they are enabled again, the slowdown returns.

The slowdown can also occur when @e selectors have no matching mobs/entities.