Shopping Cart Error when try to submit

Hello, we are getting strange error in PROD environment which we are not able to replicate in lower environments. We try to submit custom form (created via request properties). The error is

An exception has occurred while executing the form method F0_ctl00_ControlRef8_ControlRef15_ControlRef15_ControlRef8b_Main_Main_Container6_Container7_Button4_Method.

Conversion of 28/07/2025 00:00:00 to Date failed.

String was not recognised as a Valid DateTime.

We are running version 9.1

Thank you for help!