<< It is 'vipassanaayaanavaa'ti' in 'amissita-vipassanaayaana-vaa"ti'
that confuses me. how to break 'vipassanaayaanavaa'? is Please help.>>
I don't think this is a sandhi problem. I would suggest that -yaanavaa
is actually a word with the -vant suffix (like bhagavaa) and is a gloss
for -yaaniko.