AutoHotKey stopped working after plugging new keyboard, even if I restart computer - autohotkey

Question

I upgraded my keyboard. Problem is that now all the scripts stopped working. Even simple scripts from the tutorials don't work.
This happens in all applications, and ever if I plug in my old keyboard and restart the computer, autohotkey just does not work any more even in my previous configuration. I've tried also running in administrator mode.
What I do see however is the following, that the script works only once each time autohotkey is relaunced. For example:
^j::
Send, My First Script
Return
This works the first time ctrl-j is pressed, however afterwards it does not work again until I restart autohotkey.
Any ideas? I have Windows 10 x64, 1.1.23.05. I did not install any new drivers with the new keyboard (it's a standard usb keyboard, though a mechanical type).
Here are some more examples of simple scripts that don't work:
SetCapslockState AlwaysOff
In this case the first time I press the capslock, it's indeed ignored, but all the next times I click it works normally.
a::return
Again, same behaviour: a is ignored the first time, but next time it works normally, until I restart AHK (and again then it works only the first time).
Note that in all cases I'm running AHK only with the single line scripts you see; nothing else.
Below is the Key History and last lines when pressing Ctrl-J (of the first example)
Window: C:\Files\Tools\AutoHotKey\1.ahk - AutoHotkey v1.1.23.05
Keybd hook: yes
Mouse hook: no
Enabled Timers: 0 of 0 ()
Interrupted threads: 0
Paused threads: 0 of 0 (0 layers)
Modifiers (GetKeyState() now) =
Modifiers (Hook's Logical) =
Modifiers (Hook's Physical) =
Prefix key is down: no
NOTE: To disable the key history shown below, add the line "#KeyHistory 0" anywhere in the script. The same method can be used to change the size of the history buffer. For example: #KeyHistory 100 (Default is 40, Max is 500)
The oldest are listed first. VK=Virtual Key, SC=Scan Code, Elapsed=Seconds since the previous event. Types: h=Hook Hotkey, s=Suppressed (blocked), i=Ignored because it was generated by an AHK script, a=Artificial, #=Disabled via #IfWinActive/Exist, U=Unicode character (SendInput).
VK SC Type Up/Dn Elapsed Key Window
-------------------------------------------------------------------------------------------------------------
74 03F d 11.94 F5 C:\Files\Tools\AutoHotKey\1.ahk - AutoHotkey v1.1.23.05
A2 01D d 3.09 LControl *c:\Files\Tools\AutoHotKey\1.ahk - Notepad++
74 03F d 1.99 F5 C:\Files\Tools\AutoHotKey\1.ahk - AutoHotkey v1.1.23.05
Press [F5] to refresh.
Lines
001: Return (15.77)
003: if ( GetKeyState( "Control" , "P" ) )
007: Return (150.50)