Hi @gertrudgevers,
Welcome to Trend Micro Home Users Community.
We sincerely apologize for any inconvenience you experienced.
We understand that you sought assistance from Apple to address the issue, and we want to clarify that our team had already released a new version of Trend Micro Mobile Security for iOS: 11.2.1071. This update solves the problem from the previous version (11.2.1070) and reverts the changes made to Web Guard.
It's regrettable that this information wasn't communicated to you sooner, we regret any additional expense you may have incurred and any inconvenience this situation may have caused you.
If you have any further concerns or if there's anything else we can assist you with, please don't hesitate to reach out to us directly.