There is currently a bug with the reset function in bubble plugins that causes this plugin to throw an error and likely is leading to the reset issues you mentioned.
Also, FYI, Airdev is using a version of the intl-tel-input js plugin that is about 1.5-2 years old. This may not be an issue for you, but it also means that that they are not using the latest versions and changes that any countries have implemented in their phone formats via libphonenumber. These changes happen often.
I would reach out to Airdev and see if they can update their reset function. Also, I happend to noticed that the Zeroqode recently updated their Phone Number Input + Formatting for the very same reason. We decided to roll our own version of the intl-tel-input js library just because we kept running into issues such as these.