This crash happened to me several times. After the image deleted, sometimes a last slotInfoConverted() call arrives to the animation cache populator. After that the program crashes in this addConvertedFrameData() function because it tries to use a null pointer.
I'm not sure if this is a correct solution, or maybe some additional steps needed to avoid a memory leak.
This is the stack dump:
#0 KisNode::getKeyframeChannel (this=this@entry=0x0, id=...) at /home/fazekas/Asztal/krita-dev/krita/libs/image/kis_node.cpp:264
#1 0x00007f77d5daf3d8 in KisTimeRange::calculateTimeRangeRecursive (node=0x0, time=time@entry=8, range=...,
exclusive=exclusive@entry=true) at /home/fazekas/Asztal/krita-dev/krita/libs/image/kis_time_range.cpp:43
#2 0x00007f77d97255f9 in KisAnimationFrameCache::addConvertedFrameData (this=0xa1b4210, info=..., time=8)
at /home/fazekas/Asztal/krita-dev/krita/libs/ui/kis_animation_frame_cache.cpp:234
#3 0x00007f77d9726c9c in infoConverted (this=0x83890e0)
at /home/fazekas/Asztal/krita-dev/krita/libs/ui/kis_animation_cache_populator.cpp:117
#4 KisAnimationCachePopulator::slotInfoConverted (this=<optimized out>)
at /home/fazekas/Asztal/krita-dev/krita/libs/ui/kis_animation_cache_populator.cpp:359
#5 0x00007f77d7f6eed6 in QMetaObject::activate(QObject*, int, int, void**) () from /opt/qt54/lib/libQt5Core.so.5
#6 0x00007f77d7d10773 in QFutureWatcherBase::event(QEvent*) () from /opt/qt54/lib/libQt5Core.so.5
...