We recently enabled the "Force lower-case on all pageviews, event and custom variable calls" in the Google Universal Analytics tool settings, however it didn't work and we continued to see a mix of upper and lower-case letters in our accounts, in particular our pageviews. We've now resorted to implementing a filter in Google Analytics to do this for us, but we'd have preferred for this to work in the DTM settings from the beginning.
I did some testing and the force lowercase setting seemed to appropriately take effect for all pageview, event, and custom variables as expected in all of my tests. Might you be able to share a specific example of where you're seeing this issue so I can take a closer look? Feel free to send a private message if you would prefer.
Sorry for the delay. This issue was corrected in the 8/7 release. The affected property(ies) will just need to be published for this fix to take effect. Once the property is published, this setting should work as expected.
Just let me know if you continue to encounter issues or have any questions.