Release v1.8.4 fixes handling of bool properties (like enabled) for the resources dynatrace_browser_monitor and dynatrace_http_monitor.
Please be aware of the fact, that changes to synthetic monitors can be subject to a delay of multiple seconds. Executing terraform plan immediately after terraform apply where updates to resources of type dynatrace_browser_monitor or dynatrace_http_monitor are involved may therefore falsly report that a change set still exists.
A workaround for this behavior will get introduced in future versions of the provider.