My users report about bug with Multi Quote on Android 4.1.2 with Opera mini 7.6.40234.
If they select text and tap on «+ Quote» button «Insert Quotes...» didn't appear.
It they long tap on the screen then tap on «Paste» button «Insert Quotes...» appears, but couldn’t be tapped as well as button «Post Reply».
In general, we don't really support Opera Mini, particularly when it comes to more advanced operations (which multi quote and most of our JS elements would be count as). This is very likely down to the various JS limits that it has.