Hi all,
since few days i've got problem with new tickets from web from. After send, users are getting error 500 and agent see uncomplete ticket form, which is unanswerable:

Currently im using osTicket 1.18.1 at Ubuntu 24.04 (all updates installed)

//EDIT:
Now i see, that problem is also, when im trying to open ticket for other user by agent form.

My Access.log:

128.129.123.130 - - [27/Nov/2024:15:44:37 +0000] "GET /scp/logs.php?pjax=%23pjax-container HTTP/1.1" 200 3570 "https://myfqdn/scp/settings.php?t=pages" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"
128.129.123.130 - - [27/Nov/2024:15:44:38 +0000] "GET /scp/system.php?pjax=%23pjax-container HTTP/1.1" 200 2590 "https://myfqdn/scp/logs.php" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"
128.129.123.130 - - [27/Nov/2024:15:46:44 +0000] "POST /open.php HTTP/1.1" 200 5320 "https://myfqdn/open.php" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"
128.129.123.130 - - [27/Nov/2024:15:46:44 +0000] "GET /assets/default/images/icons/error.png HTTP/1.1" 200 1036 "https://myfqdn/assets/default/css/theme.css?0375576" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"
128.129.123.130 - - [27/Nov/2024:15:47:01 +0000] "POST /open.php HTTP/1.1" 500 640 "https://myfqdn/open.php" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"

And error.log

[Wed Nov 27 15:43:12.930681 2024] [proxy_fcgi:error] [pid 13995] [client 128.132.125.124:27903] AH01071: Got error 'PHP message: PHP Fatal error: Uncaught DateMalformedStringException: DateTime::modify(): Failed to parse time string (Poniedzia\xc5\x82ek 2024-11-30) at position 0 (P): The timezone could not be found in the database in /var/www/html/osTicket/upload/include/class.schedule.php:802\nStack trace:\n#0 /var/www/html/osTicket/upload/include/class.schedule.php(802): DateTime->modify()\n#1 /var/www/html/osTicket/upload/include/class.schedule.php(851): ScheduleEntry->getCurrent()\n#2 /var/www/html/osTicket/upload/include/class.businesshours.php(70): ScheduleEntry->getOccurrences()\n#3 /var/www/html/osTicket/upload/include/class.businesshours.php(106): BusinessHours->initOccurrences()\n#4 /var/www/html/osTicket/upload/include/class.schedule.php(479): BusinessHours->addWorkingHours()\n#5 /var/www/html/osTicket/upload/include/class.sla.php(55): BusinessHoursSchedule->addWorkingHours()\n#6 /var/www/html/osTicket/upload/include/class.ticket.php(557): SLA->addGracePeriod()\n#7 /var/www/html/osTicket/upload/include/class.ticke...', referer: https://myfqdn/scp/helptopics.php
[Wed Nov 27 15:43:14.663794 2024] [proxy_fcgi:error] [pid 13995] [client 128.132.125.124:27903] AH01071: Got error 'PHP message: PHP Fatal error: Uncaught DateMalformedStringException: DateTime::modify(): Failed to parse time string (Poniedzia\xc5\x82ek 2024-11-30) at position 0 (P): The timezone could not be found in the database in /var/www/html/osTicket/upload/include/class.schedule.php:802\nStack trace:\n#0 /var/www/html/osTicket/upload/include/class.schedule.php(802): DateTime->modify()\n#1 /var/www/html/osTicket/upload/include/class.schedule.php(851): ScheduleEntry->getCurrent()\n#2 /var/www/html/osTicket/upload/include/class.businesshours.php(70): ScheduleEntry->getOccurrences()\n#3 /var/www/html/osTicket/upload/include/class.businesshours.php(106): BusinessHours->initOccurrences()\n#4 /var/www/html/osTicket/upload/include/class.schedule.php(479): BusinessHours->addWorkingHours()\n#5 /var/www/html/osTicket/upload/include/class.sla.php(55): BusinessHoursSchedule->addWorkingHours()\n#6 /var/www/html/osTicket/upload/include/class.ticket.php(557): SLA->addGracePeriod()\n#7 /var/www/html/osTicket/upload/include/class.ticke...', referer: https://myfqdn/scp/helptopics.php
[Wed Nov 27 15:47:01.215298 2024] [proxy_fcgi:error] [pid 7531] [client 128.132.125.124:27988] AH01071: Got error 'PHP message: PHP Fatal error: Uncaught DateMalformedStringException: DateTime::modify(): Failed to parse time string (Poniedzia\xc5\x82ek 2024-11-30) at position 0 (P): The timezone could not be found in the database in /var/www/html/osTicket/upload/include/class.schedule.php:802\nStack trace:\n#0 /var/www/html/osTicket/upload/include/class.schedule.php(802): DateTime->modify()\n#1 /var/www/html/osTicket/upload/include/class.schedule.php(851): ScheduleEntry->getCurrent()\n#2 /var/www/html/osTicket/upload/include/class.businesshours.php(70): ScheduleEntry->getOccurrences()\n#3 /var/www/html/osTicket/upload/include/class.businesshours.php(106): BusinessHours->initOccurrences()\n#4 /var/www/html/osTicket/upload/include/class.schedule.php(479): BusinessHours->addWorkingHours()\n#5 /var/www/html/osTicket/upload/include/class.sla.php(55): BusinessHoursSchedule->addWorkingHours()\n#6 /var/www/html/osTicket/upload/include/class.ticket.php(557): SLA->addGracePeriod()\n#7 /var/www/html/osTicket/upload/include/class.ticke...', referer: https://myfqdn/open.php

I've applied this pull but error is still the same:
https://github.com/osTicket/osTicket/pull/6699/commits/f2facda3e64be2404316048eb31d89309fb64292