SUMMARY
This bug appears when using KWin's Zoom effect, in conjunction with KDE Connect remote control. It might be a bug either in KWin or in KDE Connect.
KWin : version 5.12.6 LTS
kdeconnect-kde : version 1.3.3
Remote control kdeconnect plugin : version 0.1

When the view is zoomed using KWin's zoom effect, it normally follows the cursor when it is moved through regular mouse movement.
KDE Connect has a "remote control" plugin which allows to move the cursor of a computer from your smartphone, through the KDE connect app. The view doesn't follow the cursor when it is moved through KDE Connect

STEPS TO REPRODUCE
1. Install KDE connect on both computer and smartphone. Check that the remote control plugin is activated in KDE Connect's parameters on the computer.
2. Use KWin Zoom effect (default Meta + '+')
3. Use the remote control on the smartphone to move the cursor

OBSERVED RESULT
The view does not follow the cursor, while it does if the cursor is moved using a mouse/touchpad.

EXPECTED RESULT
The view should follow the curosr

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: openSUSE 15
(available in About System)
KDE Plasma Version: 5.12.6
KDE Frameworks Version: 5.45.0
Qt Version: 5.9.4

ADDITIONAL INFORMATION
My system is in French. The exact name of the plugin in English might be different from "remote control".
I am running an LTS version of Plasma, this bug should be confirmed with the latest versions of both KWin and kdeconnect-kde.
I have also reported this bug against kdeconnect : https://bugs.kde.org/show_bug.cgi?id=403859