Spanned clips happen for two reasons: if a single video file size on the P2 exceeds 4 GB (since P2s are formatted in FAT32…and I always thought this limit was 2 GB, but the FCP manuals say 4 GB), OR if a single video recording begins on one card and continues on the second.
When pulling spanned clips in to FCP (clips A and B for example, A being the first half of the clip), you don’t have to import both clips from your different P2 reels. FCP and the P2 Import Window recognize that A and B are spanned clips that together make up one clip, despite the fact that the occur on different reels/cards. If you import both A and B, you will get two clips in FCP that are exactly the same, although they will each be named their respective name. You only need to import A or B, and it’s best to change the reel name from “Spanned Clip” to a name that is more recognizable if you ever need to pull the footage in again.
Not sure why you’re getting dropouts though. I just checked some of our recent P2 footage with spanned clips and nothing dropped.
-Ben