LocalizedTextUtil reports WARNings when app uses more than one resource bundle

In my app I use 3 resource bundles. One of them is located direclty in the app and contains most text keys. The other two are located in JARs that are reused in several apps and bring a few own text keys.

Each Key is defined in exactly one bundle.

Since Version 2.3.18 LocalizedTextUtil searches each key in all bundles and reports WARN messages for those bundles the key is not located in:

WARN opensymphony.xwork2.util.LocalizedTextUtil - Missing key [...] in bundle [...]!

Is is probably caused by WW-4379.