Problem with Moving Multiple Clips in Timeline - Some Disappear

The issue I am having is when I select multiple clips in the timeline and then try to move or nudge them, some of the clips disappear. I used Pro-Tools Version 8 for years and never had the problem until I upgraded to 11. I just selected as many clips as I wanted and then moved all of them at once, to wherever I wanted. I've tried all of the link buttons but can't seem to find a solution. Also, when trying to consolidating clips sometimes, it will only consolidate some and leave another part of the clip separate....quite odd. I imagine it probably is a simple fix...unless it is some bug in my software. Everything else works well though and I have re-installed the software twice. Anyone seen this before or know the solution? Thanks much for the assistance.