[TYPO3-english] Powermail Pre-filling from records

[Matt Clough]

Hi All,
I am having a problem with Powermail and prefilling values. Some background:
I have created an extension that extended tx_news with some additional fields for events, such as start date, start time, location etc. The event article contains a link to a Powermail registration form containing the uid of the event article.

On the form page I have some TypoScript that pre-fills certain fields with the event information. An example for pre filling the location field is below:

lib.eventRegistrationLocation = RECORDS
lib.eventRegistrationLocation {
    dontCheckPid = 1
    tables = tx_news_domain_model_news
    source.data = GP:event|tx_news
    conf.tx_news_domain_model_news = TEXT
    conf.tx_news_domain_model_news {
        field = event_location
        required = 1
    }
}
plugin.tx_powermail.settings.setup.prefill {
    # Fill field with marker {location}
    location < lib.eventRegistrationLocation
}

This work fine on Powermail up to version 2.5.2, But on any version higher I get a problem when the content of the field is empty.
For example, if no end date has been added to the event, the value of the prefilled field in Powermail is set to 'RECORDS'. In version 2.52 and lower, the value is just left blank. 

Has something changed in the way Powermail handles prefilling fields, especially fields with empty values?

Any help and advice would be most appreciated.

All the best

Matt