OK, I've researched this topic in various threads, and while many report the same as what I've experienced, the GREAT dissappointment is that this problem appears to have been totally neglected in the 4.1 patch. What a shame.
To revisit: When editing in HDV certain portions of sequences containing effects or transitions playback the Yellow "Media Pending" graphic even though source files play just fine AND all FX are "rendered." No changes to sources file names (i.e. - not an .xmp file link issue). No reason for this to occur at all, really. And there seems to be no apparent rhyme or reason as to when and where this ocurrs.
I can't find anyone reporting this work around: The problem goes away when you nest the sequence segment in question, but you have to re-render and re-apply FX and transitions.
Sure, restarting PPro helps, but we've been frustrated by rendered portions of the timeline mysteriously becoming unrendered.
ANYONE have a solution (other than nexting the segments in question)?
All this (post 4.1) crap still makes me want to flush PPro CS4 down the toilet. Saving up for FCP!