Monolingual text properties do not allow the pipe character as part of the value. The pipe character and everything after it is silently removed when saving.

For example:

• Load https://www.wikidata.org/wiki/Q4115189
• Start adding a "Sandbox Monolingual text" property
• Add "Test1 | test2" as the value
• Select a language for the value
• Save

Expected result: The value saved is "Test1 | test2"
Actual result: The value saved is "Test1"

If the pipe character is the first character, it fails to save instead, giving the error Must be at least one character long.

String properties do not have this problem.