With recent IOS version [14.5.1], my ion-botton started behaving strange while toggling the disabled property.
When changed from disabled to non-disabled, the ion-button gets active but its label still remains disabled.
This is likely due to a bug in WebKit with iOS 14.5 (see: bug: ios 14.5, variables changes not being rendered with pointer-events property · Issue #23256 · ionic-team/ionic-framework · GitHub). The bug has already been fixed on Apple’s end, we are just waiting for the fix to ship in an upcoming release of iOS.