The tag is present in Lintian version 2.104.234. That is the most recent version we know about.
The dependency_libs field in the .la file has not been cleared. It has long been a release goal to get rid of unneeded .la files and clearing the dependency_libs field from the rest of them.
A non-empty dependency_libs field will also stall the Multi-Arch conversion.
The .la file in itself may be useful if the library is loaded dynamically via libltdl.