Hi Jiri,
Usually these types of problems on not specifically related to the RESET pin, but the burst getting into the ADS1217 through power supply or analog input pins which cause the device to go into a reset condition. You did not specify whether the bursts are ESD (high voltage) or EMI/RFI. Extra ESD protection diodes can be added if needed, or additional filtering is also possible if related to EMI/RFI. Sometimes these problems can be improved with PCB layout changes.
Please let me know the specifics of the tests and send me your schematic and layout and I can help identify areas of concern.
Best regards,
Bob B