Pattern appeared on painted wallpaper

Have HUGE wallway. Is my job to decorate it. Have stripped bottom part of wall (we have dado) but top is plain flat paper (might be lining paper) which has just been painted a couple of times. Intended to wallpaper over it but on washing cornice wall got wet and bubbles appeared. Does this mean existing paper isn't firmly stuck to wall enough to cope with being papered over? Am already losing will to live and can't face stripping vast amount of what appears to be very stubborn wallpaper (I tested a bit to see if it comes off easily).