No fields and no labels in email

Chronoforms6 has been working perfectly since 2 years but during the last 2 days is now sending empty mails (not a single fields in it) with only the Body text.

The validation and recaptcha are working fine and I cannot reproduce this error on my side.

The only change I made recently was to add {:IP} in the Subject line. Could it be the problem?

All this with
Joomla 3.9.8
ChronoengineGcore2 V1.0 2017
ChronoForms6 V6.1.4 June 2019
Chronoforms6 Plug-in V6.0 April 2017
ChronoForms6 Module v6 April 2017
ChronoForms6 Package V 6.1.2

Thanks for your insight. This form is used for restaurant booking and this is really a big trouble for us.

Do you maybe mean {ip:} ?

Do you have the form inside an article ? and does your website have the cache enabled ? if yes then try to disable the "Chronoforms6 Plug-in V6.0"

Yes I do... The line was "Booking received from {ip:}" in subject

Thanks admin. I'll try that and I let you know what happens