Randomly losing Sendgrid API key?

I use the Sendgrid API connection in Fluent SMTP on all my website, and I’ve noticed over the past several months that the API key will randomly get removed from the settings, and I must re-add it. It doesn’t happen on every website, and considering we’re talking over 200 websites here it’s a bit hard to pin-point why it happens to some and not others. I don’t get any kind of email notification that the keys were removed, which is frustrating because until I log into the website I have no idea that emails aren’t being sent.

A few things that are common on all these sites are:

• Hosted on Siteground
• Majority have Elementor Pro
• Majority have the Siteground Optimizer plugin
• Auto-update is enabled for plugins and themes
• Standard WordPress CRON is disabled, we setup our own that runs twice every hour
• When the API key does get removed, it’s replaced by 4 characters (I don’t know what they are)

I suppose adding a back-up connection would help, but it doesn’t address the issue of why it’s happening in the first place. Some clients had no idea they even got orders because FluentSMTP lost the Sendgrid API key and never sent them the email notification.