Prescription does not show route and interval any more

The prescriptions stopped showing the route and interval, and any edits in the drug prescription form in these fields are not saved. I use Oemr 5.01(6).
I also do some developing on an older 5.01-dev installation that does not have this problem, there it works. Replacing the /templates/prescription/general_edit.html with the one from the working installation however doesn’t work.
I know that there is a setting “Simplified prescriptions” in the globals, but that is turned off in both installations. Only the older dev-version works, but the new 5.01(6) does not.
The log reads:

[client 127.0.0.1:55622] PHP Notice: Undefined property: C_Prescription::$prescriptions in /var/www/openemr/controllers/C_Prescription.class.php on line 99, referer: http://localhost/openemr/controller.php?prescription&list&id=49
[Mon Feb 11 03:10:41.902170 2019] [:error] [pid 8746] [client 127.0.0.1:55626] PHP Notice: Undefined index: disp_button in /var/www/openemr/controllers/C_Prescription.class.php on line 199, referer: http://localhost/openemr/controller.php?prescription&edit&id=324

Could someone shed a light on where to look? If I edit the drug in the inventory it also does not save the interval:

Undefined index: form_orderby in /var/www/openemr/interface/drugs/drug_inventory.php on line 35, referer: http://localhost/openemr/interface/main/tabs/main.php
[Mon Feb 11 03:14:18.130552 2019] [:error] [pid 9375] [client 127.0.0.1:55662] PHP Notice: Undefined index: in /var/www/openemr/interface/drugs/drug_inventory.php on line 35, referer: http://localhost/openemr/interface/main/tabs/main.php

what is going on? Please help
Roland :paw_prints: