Plugin crashes from time to time on getIssue FieldValue method on issues with no priority set

[DummyThatMatters]

I cant name exact steps to reproduce the issue, but we have plugin failures from time to time with following error in the logs:

"msg":"Plugin failed to ServeHTTP, RPC call failed","plugin_id":"jira","error":"connection is shut down"}
"msg":"Plugin failed to ServeHTTP, muxBroker couldn't accept connection","plugin_id":"jira","serve_http_stream_id":2922,"error":"timeout waiting for accept"}
"msg":"Health check failed for plugin","id":"jira","error":"Plugin RPC connection is not responding"}
"msg":"error closing client during Kill","plugin_id":"jira","wrapped_extras":"errconnection is shut down"}
"msg":"RPC call OnDeactivate to plugin failed.","plugin_id":"jira","error":"connection is shut down"}
"msg":"plugin failed to exit gracefully","plugin_id":"jira"}
"msg":"Access to route for non-existent plugin"

On log level turned to debug we observed following error message over and over again:

[signal SIGSEGV: segmentation violation code=0x1 addr=0x30 pc=0xb2905e]
panic: runtime error: invalid memory address or nil pointer dereference
/mnt/d/Documents/MyProj/Jobs/RTK/Sources/plug-ins/mattermost-plugin-jira/server/issue.go:867 +0x1be
goroutine 67 [running]:
main.getIssueFieldValue(0xc0004c5410, 0xc0003fa1a0, 0x8, 0x1)
.../mattermost-plugin-jira/server/subscribe.go:162 +0x292
.../mattermost-plugin-jira/server/subscribe.go:187 +0x238
main.(*Plugin).getChannelsSubscribed(0xc0002f4600, 0xc0000c4960, 0xc0005f2000, 0x13, 0x0, 0x0, 0x0, 0xc8, 0x0)
main.(*Plugin).matchesSubsciptionFilters(0xc0002f4600, 0xc0000c4960, 0xc0008fd320, 0xc0008fd350, 0xc0008fd380, 0xc0005f4460, 0x1, 0x4, 0x0)
main.webhookWorker.work(0x6, 0xc0002f4600, 0xc00010f800)
.../mattermost-plugin-jira/server/webhook_worker.go:69 +0x2a5
main.webhookWorker.process(0x6, 0xc0002f4600, 0xc00010f800, 0xc000303590, 0x0, 0x0)
Plugin failed to ServeHTTP, RPC call failed","plugin_id":"jira","error":"connection is shut down

It seems that error appears when someone do some operation with ticket that have no priority field set.