Details here. I see it on Linux gtk2 x64 too.
https://forum.lazarus.freepascal.org/index.php/topic,48617.0.html
What is wrong with atsynedit?
Stacktrace
#0 CLASSES$_$TWRITER_$__$$_WRITEPROPERTY$TPERSISTENT$POINTER at :0 0000001 CLASSES$_$TWRITER_$__$$_WRITEPROPERTIES$TPERSISTENT at :0 0000002 ?? at :0
0000003 ?? at :0
0000004 ?? at :0
0000005 ?? at :0
0000006 ?? at :0
0000007 ?? at :0
0000008 ?? at :0
0000009 ?? at :0
0000010 ?? at :0
0000011 ?? at :0
0000012 ?? at :0
0000013 ?? at :0
0000014 ?? at :0
0000015 ?? at :0
0000016 CLASSES$_$TWRITER_$__$$_WRITEPROPERTIES$TPERSISTENT at :0 0000017 ?? at :0
Regards,
Alexey