After disconnecting from wifi I must "killall wpa_supplicant" before I can reconnect

Question

Everytime I disable wifi or lose connection to that network I must do a "killall wpa_supplicant" before I can reconnect. If I don't do that, the system keeps saying "[my-chosen-wifi-point] is disconnected, you are offline" every 30 seconds until I do the killall thing.

I have a recently (2 days ago) updated Ubuntu system.

When looking for a solution I found a similar problem here but the solutions there would not work for me well as I need to be able to occassionally dynamically change wifi access points (when I move around a bit):

Need to restart network interfaces and kill wpa_supplicant, how to fix?

Additionally when I digged around in syslog, I found the following suspicious error messages: "NetworkManager nl_recvmsgs() error: (-33) Dump inconsistency detected, interrupted". A quick Google search for this message turned out an as-of-today-unfixed 1 years old bug here (or it is unfixed according to Bugzilla):

https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1118446

Additionally, this issue started when once the machine with my Ubuntu crashed (ran a program with root rights that had a "poweroff" kernel call embedded in it, caused instant unclean power down, after booted up the NetworkManager/wpa_supplicant combo appeared to not recover properly and the wifi is broken like this since then).

What I would like to know is where exactly is that "dump" about whose "inconsistency" the NetworkManager is complaining so I can do a rm -[r]f on it to get rid of the problem. Or is there anything else wrong out there?

I also think the answer to the question(s) in the last paragraph could help with more questions, for example:

Ubuntu disconnecting from wifi

Also note to myself. This answer could provide a somewhat working solution:

How do I run a simple Zenity script after disconnecting from WiFi?

The trick is to tell the system to "killall wpa_supplicant" when network is down. But I am not sure whether it is going to work correctly (I don't want the wireless to die when I disconnect a wired connection for example). And it will not help much with my reconnect on access point change problem.