Thanks all. I know it's not me now. I did try 3 linux flavours, new profiles, new installs, all 64 versions behave the same way, failing intermittently. Now using the last 63 version until its fixed.
Linux Ver. 64.0.3417.47-1 and the latest 64.0.3417.54-1 do not remember pinned tabs correctly. Reverting to 63.0.3368.94-1 it then never fails to remember correctly.
Have tried on 2 PCs.
Can anybody confirm wether this is my linux or Opera.