Steps to reproduce:

1. Login as super administrator.
2. Create host groups HOST_GROUP_A and HOST_GROUP_B.
3. Create a host HOST and assign it to the HOST_GROUP_A.
4. Create a discovery rule DISCOVERY_RULE for the HOST.
5. Create a HOST_PROTOTYPE for the DISCOVERY_RULE of the HOST and assign it to the HOST_GROUP_A and HOST_GROUP_B (use {#NAME} as name).
6. Create a user group USER_GROUP and assign it read-write permissions to the HOST_GROUP_A.
7. Create a user USER of type Zabbix Admin and assign it to the USER_GROUP.
8. Login as USER.
9. Open the HOST_PROTOTYPE of the DISCOVERY_RULE of the HOST.
10. Notice in the Groups tab that only HOST_GROUP_A is presented (HOST_GROUP_B is not accessible to the USER).
11. Click Update and notice a Host prototype updated message.
12. Login as super administrator.
13. Open HOST_PROTOTYPE of the DISCOVERY_RULE of the HOST.

Result:

HOST_PROTOTYPE is now assigned only to the HOST_GROUP_A, but not to the HOST_GROUP_B.

Expected:

HOST_PROTOTYPE should be still assigned to both HOST_GROUP_A and HOST_GROUP_B.