I have the same issue. I fix it by turning off PopClip and triggering its context menu with help of Alfred. Another solution would be pressing Command key while selecting text, this deactivates PopClip.
I’ve made a simple Alfred workflow that triggers from the keyboard (double tap Shift) and makes PopClip appear for the currently selected text. Unfortunately I don’t see how to attach it here. I’ve taken info from how to control PopClip using AppleScript.