"Subscriptions" plugin: Webserver error log: "Undefined index: subscriptions" in Main.php:33

[neilr8133]

With the "Subscriptions" plugin installed, whenever a post is made (and possibly at other times though I have not confirmed that), I see the following in my webserver error logs:

PHP Notice:  Undefined index: subscriptions in /var/www/IdnoPlugins/Subscriptions/Main.php on line 33, referer: https://blahblahblah/admin/users

Looking at the line, it appears to be a reference to $user->notifications['subscriptions'] but I can't figure out what to do about it: I tried restarting the webserver and going into my user setting and re-saving it (to try and force it to re-write my preferences including the opt-in/out status of the Subscription setting), but I still get the error. (I must also note that messages are apparently still sent, so it's unclear to me what the repercussions of this error could be.)