Werk #19063: Prevent invalid regex when combining expressions

Component	Checks & agents
Title	Prevent invalid regex when combining expressions
Date	Jan 13, 2026
Level	Trivial Change
Class	Bug Fix
Compatibility	Compatible - no manual interaction needed
Checkmk versions & editions	2.6.0b1 Not yet released Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT 2.5.0b1 Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT 2.4.0p20 Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT 2.3.0p43 Checkmk Community, Checkmk Pro, Checkmk Ultimate, Checkmk Ultimate MT

Werk 17075 introduced a fix that prevented expressions from becoming invalid during concatenation when they contained global flags.

However, this fix was not applied everywhere. The "Check_MK Discovery" was still affected and would show a UNKN state with this error message:

"Invalid regular expression '...': global flags not at the start of the expression at position 1"

Now, the fix from werk 17075 is also applied for periodic service discovery. No manual interaction is required to benefit from this fix.

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