Quick Actions - Language changes randomly

Summary

Navigate from Me > Show More or from My Client Groups > Show More, the quick action Headings eg Employment, Compensation, Payroll are appearing in a different language

Content

We have noticed over the last couple of days that our Production pod is randomly changing the headings for our quick actions into different languages, so far I've experienced this in both Czech and Spanish, whilst the quick actions themselves remain in English. 

My language preference is set to English.

Clearing the cache and logging out / in again seems to resolve the issue temporarily and then it returns.  This is happening to a number of users, not just myself.