The bool type functions located on the RunService page all contain code samples which will error on runtime due to an arbitrary code block discriminator located on the first and last line of each sample.
For example, navigate to the RunService:IsServer() function and paste the code sample into a script. On runtime, you will get a warning and the script will fail to execute due to the arbitrary discriminators located on the first line.
Error
The same issue is present on the following pages: RunService:IsClient(), RunService:IsRunMode(), RunService:IsRunning(), RunService:IsStudio() and RunService:IsServer().
Solution: Remove the code discriminators from the code samples.