This issue is reproducible in
ui/tests/integration/testCalculatedExpression.php test, but was silenced in

https://git.zabbix.com/projects/ZBX/repos/zabbix/pull-requests/11058/diff#ui%2Ftests%2Fintegration%2FtestCalculatedExpression.php

since according to docs the maximum supported value is 1.79E+308
https://www.zabbix.com/documentation/7.0/en/manual/appendix/install/db_float_range

It would be preferable to add checks on server side to make item unsupported when double value is outside the -1.79E+308 to 1.79E+308 range.
So, C DBL_MAX value of 1.7976931348623157e308 should NOT be accepted.

Prediction timeleft() function now returns DBL_MAX or 1.7976931348623157e308
https://www.zabbix.com/documentation/current/en/manual/appendix/functions/prediction
It may need to be updated.