Jira 8 - Query Issue Custom Fields Plugin, Green plus sign not working

[D T]

Does anyone experience this bug in Jira 8.3/8 with the Query Issue Custom Fields Plugin, when you try to click on the green sign next to the custom field, it returns an error?

Green button apart of 'Query Issue Custom Fields' plugin

Error logs:

java.lang.NumberFormatException: null
	at java.lang.Long.parseLong(Long.java:552) [?:1.8.0_102]
	at java.lang.Long.valueOf(Long.java:803) [?:1.8.0_102]
	at ru.mail.jira.plugins.lf.MailRuQueryPickerAction.doExecute(MailRuQueryPickerAction.java:91) [?:?]
	at webwork.action.ActionSupport.execute(ActionSupport.java:165) [webwork-1.4-atlassian-30.jar:?]
	at com.atlassian.jira.action.JiraActionSupport.execute(JiraActionSupport.java:63) [jira-api-8.3.0.jar:?]

I can see in the url it's missing the project id value:

''http://myjira.com/secure/popups/MailRuUserPickerValuePickerAction.jspa?cfid=customfield_14828&inputid=customfield_14828&returnid=customfield_14828''

when I copy paste the url into the browser and inserted the project id manually, it works.

'http://myjira.com/secure/popups/MailRuUserPickerValuePickerAction.jspa?cfid=customfield_14828&inputid=customfield_14828&returnid=customfield_14828&prId=13731''

So I assume this is a plugin bug, a fix for the developers?

Anyway if you have a workaround, I would greatly appreciate it if you could help me out.

Regards,

David