some time ago we faced with similar looking error (Method not found: 'System.Threading.Tasks.Task`1<...>) but with different actual types: Method not found error in UnifiedGroupsUtility.ListUnifiedGroups() when use PnP.Framework 1.6.0 with newer version of Microsoft.Graph. In our case it was caused by dependency update - details are described in blog post. Not sure will it help in your case but may be also related with dependencies update.
Method not found : Azure.Messaging.ServiceBus
cnk
1
Reputation point
platform : In azure functions portal, .net core, 64bit
for a couple for months, calling SendMessageAsync and SendMessagesAsync work without fail. Today I was wondering why messages are not being sent to queue. I get this error
Method not found: 'System.Threading.Tasks.Task`1