This may not have been desired, to have some components suppressed. This is a performance thing and in this case it may not have really helped. Manually unsuppressing each item is tedious. You could shift or ctrl select the multiple items in the Feature Manager Tree and unsuppress/set to resolved.
Or, better yet, get it right the first time.
Tools, Options, System Options, Assemblies.
Turn on Use Large Assembly Mode and set the value for components higher, like 5,000 instead of 500. Then re-open/re-import the Large Iges file. More items should come in resolved.
Note: You may want to set this back the way it was after. Remember it's a performance thing, but in this case it may have just gotten in the way.
Jim Krivoshein, CSWP
Computer Aided Technology, Inc.