Errors when viewing and exporting data

Hi,

I’m receiving several errors when trying to view and export cfdb7 entries:
In the list view: Warning: Invalid argument supplied for foreach() in XXXX/wp-content/plugins/contact-form-cfdb7/inc/admin-subpage.php on line 241

One entry is missing all fields in the list view, except the date. Upon opening this entry’s detail view, the following error occurs and the entry is deleted from the DB (I checked the MySQL table): Warning: Invalid argument supplied for foreach() in XXX/wp-content/plugins/contact-form-cfdb7/inc/admin-form-details.php on line 48

When trying to export CSV, the ‘headers already sent’ error occurs:
Warning: Invalid argument supplied for foreach() in XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php on line 89
Warning: Cannot modify header information – headers already sent by (output started at XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php:89) in XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php on line 18
Warning: Cannot modify header information – headers already sent by (output started at XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php:89) in XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php on line 20
Warning: Cannot modify header information – headers already sent by (output started at XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php:89) in XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php on line 23
Warning: Cannot modify header information – headers already sent by (output started at XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php:89) in XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php on line 24
Warning: Cannot modify header information – headers already sent by (output started at XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php:89) in XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php on line 25
Warning: Cannot modify header information – headers already sent by (output started at XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php:89) in XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php on line 28
Warning: Cannot modify header information – headers already sent by (output started at XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php:89) in XXX/wp-content/plugins/contact-form-cfdb7/inc/export-csv.php on line 29

WP v4.9.6
Contact Form 7 v5.0.2
CFDB7 v1.2.2.
Checked with PHP 5.6, 7.0 and 7.1

What could possibly cause this?

Thanks in advance!