Flows stopped due to missing node types - spontaneously

While working on some flows, deploying, editing, deploying etc.

When I deploy sometimes, I get "no response from server" - where node-red restarts and this popup suddenly shows up: "Flows stopped due to missing node types" - for openzwave-am and ttn app, these nodes have giving me problems since the last update of node-red (don't think it is related).

The last message is:

- /home/administrator/.node-red/node_modules/node-red-contrib-ttn/ttn-app/ttn-app.js
- /usr/lib/node_modules/node-red/node_modules/@node-red/registry/lib/loader.js
- /usr/lib/node_modules/node-red/node_modules/@node-red/registry/lib/index.js
- /usr/lib/node_modules/node-red/node_modules/@node-red/runtime/lib/nodes/index.js
- /usr/lib/node_modules/node-red/node_modules/@node-red/runtime/lib/index.js
- /usr/lib/node_modules/node-red/lib/red.js
- /usr/lib/node_modules/node-red/red.js
10 Aug 08:48:18 - [warn] [node-red-contrib-openzwave-am/zwave] Error: The module '/home/administrator/.node-red/node_modules/openzwave-shared/build/Release/openzwave_shared.node'
was compiled against a different Node.js version using
NODE_MODULE_VERSION 64. This version of Node.js requires
NODE_MODULE_VERSION 72. Please try re-compiling or re-installing
the module (for instance, using `npm rebuild` or `npm install`). (line:43)

I go to both nodes and do rebuild followed by install, restart node-red and it works again - for a while.
How come that it suddenly evaluates these nodes and fails ?