Hi @josvanesch,
Could you please share a screenshot of your flow's configuration?
Do you add a "Send email with options" action within your flow?
I suppose that you add a "Send email with options" action within your flow, is it true? I agree with @ScottShearer's thought almost, if you add the "Send email with options" action within your flow, this operation would send an email to the recipient with multiple options, then wait for the recipient to respond back with one of those options.
If the recipient doesn't make a response (choose an option) to this email, the "Send email with options" action would be running continuously.
More details about the "Send email with options" action of Office 365 connector, please check the following article:
Send email with options
Please check and see if the following blog would help you understand the "Send email with options" action:
https://syscloudpro.com/2018/02/08/microsoft-flow-approval-email-send-with-options/
Best regards,
Kris
