Hello Andrea,
>> On another vlan, I'm receiving multicast traffic (I'm not able to be more specific about this type of traffic) from a router and this traffic should reach host on the same vlan.
If that router is a multicast router (and it should be if it forwarding multicast traffic ) you don't need the IGMP snooping querier in that specific vlan it can be performed by the router itself
IGMP snooping querier is a subset of features and does not deal with PIM DR election so it shouldn't be used on that vlan
as a starting point you can also disable IGMP snooping on that vlan to see what happens
Hope to help
Giuseppe