I'm still seeing this issue, and it's inconsistent. When filtering by a tag, notes will show up in the list, then later (same day or next day) there will be a huge gap. It's extremely noticeable because I have notes from weekly meetings and sometimes there are major gaps in meetings (weeks, sometimes up to 6 months). I find it hard to believe it's a synchronization problem because these are not new notes that are missing (well over days old).
My notes are almost 100% text, I rarely attach files, the Evernote folder is only 61MB.
This as well as the overall brutal performance and large system load have made me switch back to the legacy version, I find version 10.x unusable.