Occasionally, I use a very specific custom field title which it would be useful to be able to search for. As far as I know, custom field titles are not included in a search.

The bug is a different thing but probably more worthy of being addressed than my request which is unlikely to be an issue for most people. I meant that I wanted the actual title of the custom field to be included in search results e.g. "username for website" or whatever the name of the custom field is (as opposed to its contents) but this is really only to cater for the situation where I have included some information in a custom field on a record but I can't remember which record it is in. The iOS bug is something I had noticed but I hadn't twigged what its cause was - your explanation makes sense i.e. iOS isn't including custom fields added to a preset type in its search. That does need fixing.