it's close to a clone of ZBXNEXT-5929 but both should be addressed in my opinion

the most common scenario of the "execute now" button is trigger, pre-processors, dependent or calculated item development.

when doing this, it is very frustrating to not have "Execute now" returns a value shortly due do it being filtered out by the "discard unchanged" processor.

Since "Execute now" instructs a proxy to fetch the value, it should be possible to send a "fetch and don't discard a value" instruction.

regarding ZBXNEXT-5929, maybe cleaning the history for one table could also send that instruction, but that is a separate discussion to be held under that jira issue.