Title pretty much says it.
A:
1. copy an object
2. paste
3. try to navigate to target area by panning using middle button
Object is placed where you middle-clicked
B:
1\. Start drawing a line or a segment of copper area
2\. Pan using the middle button
Line / segment gets a point added where you middle clicked
For me this happens on MacOS, haven't tried in Win/Linux.
Chrome
77.0.3865.90
OS X
10_14_5
EasyEDA
6.2.46