Can you file bug reports where permanent items like tags are not preserved? That would be a problem regardless whether a last view is to be shown.
Persistence of Fitler gramplet parameters were occasionally causing purging of Custom Filters (particularly when moving between machines with different add-on installations) and endless loops.
If you want to save complex Filter Gramplet parameter sets for re-use, try the Filter+ addon gramplets from Isotammi. It can scrape the parameters into a new Custom Filter.
The Relationship category’s experimental CardView in bridges the data display in this manner. Including having an Age calculated and displayed for the various Events.