How to force sharepoint to stop returning search results for defunct claims provider?

Question

I had installed a custom claims provider, and used it to search for and add some users via the claims picker.

Now, I have removed the claims provider, and via powershell, removed the corresponding user profiles and user records. I can verified the user and profile records and the claims provider are gone via

Get-SPUser -Web https://theweburl:3443

(New-Object Microsoft.Office.Server.UserProfiles.UserProfileManager(Get-SPServiceContext (Get-SPSite https://theweburl:3443))).GetEnumerator()

Get-SPClaimProvider

However, even though the 3 above commands show absolutely no references to the claims provider or user accounts referenced by the claims provider, the search results in the people picker still find some users originally associated with the provider (though attempting to actually share a site with the defunct user will result in an error because the user doesn't exist).

How can I get SharePoint to stop returning these now defunct claims in the claim picker?

Update: Not sure if this is related or not, but I am noticing errors in the Windows event log such as:

The Execute method of job definition Microsoft.Office.Server.UserProfiles.LMTRepopulationJob (ID 8e98bd09-f599-4c63-baf9-89fcbb2e8f16) threw an exception. More information is included below.

Unexpected exception in FeedCacheService.IsRepopulationNeeded: Connection to the server terminated,check if the cache host(s) is running .

LogName: Application
Source: SharePoint Foundation
Event ID: 6398
Level: Critical
OpCode: Info
TaskCategory: Timer

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
 <System>
   <Provider Name="Microsoft-SharePoint Products-SharePoint Foundation" Guid="{6FB7E0CD-52E7-47DD-997A-241563931FC2}" /> 
   <EventID>6398</EventID> 
   <Version>15</Version> 
   <Level>1</Level> 
   <Task>12</Task> 
   <Opcode>0</Opcode> 
   <Keywords>0x4000000000000000</Keywords> 
   <TimeCreated SystemTime="2014-12-17T11:45:00.783070300Z" /> 
   <EventRecordID>160828</EventRecordID> 
   <Correlation ActivityID="{D9A3D69C-288D-30E5-00DD-87AE36592E7D}" /> 
   <Execution ProcessID="2112" ThreadID="2172" /> 
   <Channel>Application</Channel> 
   <Computer>(redacted)</Computer> 
   <Security UserID="(redacted)" /> 
 </System>
 <EventData>
   <Data Name="string0">Microsoft.Office.Server.UserProfiles.LMTRepopulationJob</Data> 
   <Data Name="string1">8e98bd09-f599-4c63-baf9-89fcbb2e8f16</Data> 
   <Data Name="string2">Unexpected exception in FeedCacheService.IsRepopulationNeeded: Connection to the server terminated,check if the cache host(s) is running .</Data> 
 </EventData>
 </Event>

And a slightly different variant:

 The Execute method of job definition Microsoft.Office.Server.UserProfiles.LMTRepopulationJob (ID 8e98bd09-f599-4c63-baf9-89fcbb2e8f16) threw an exception. More information is included below.

 Unexpected exception in FeedCacheService.BulkLMTUpdate: Region not found..

LogName: Application
Source: SharePoint Foundation
Event ID: 6398
Level: Critical
OpCode: Info
TaskCategory: Timer

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
   <Provider Name="Microsoft-SharePoint Products-SharePoint Foundation" Guid="{6FB7E0CD-52E7-47DD-997A-241563931FC2}" /> 
   <EventID>6398</EventID> 
   <Version>15</Version> 
   <Level>1</Level> 
   <Task>12</Task> 
   <Opcode>0</Opcode> 
   <Keywords>0x4000000000000000</Keywords> 
   <TimeCreated SystemTime="2014-12-17T11:05:07.261317200Z" /> 
   <EventRecordID>160815</EventRecordID> 
   <Correlation ActivityID="{8FA1D69C-188F-30E5-00DD-8DD5E1F2207D}" /> 
   <Execution ProcessID="2112" ThreadID="2148" /> 
   <Channel>Application</Channel> 
   <Computer>(redacted)</Computer> 
   <Security UserID="(redacted)" /> 
 </System>
 <EventData>
   <Data Name="string0">Microsoft.Office.Server.UserProfiles.LMTRepopulationJob</Data> 
   <Data Name="string1">8e98bd09-f599-4c63-baf9-89fcbb2e8f16</Data> 
   <Data Name="string2">Unexpected exception in FeedCacheService.BulkLMTUpdate: Region not found..</Data> 
 </EventData>
 </Event>

Answer 1

The first thing I would do is run the following

STSADM.EXE -o Sync -listolddatabases 30
STSADM.EXE -o Sync -deleteolddatabases 30

The second command is only necessary if the first one returns results.

If you for some reason the user is still showing up, Even thought the Get-SPUser is not returning the user I would manually check the userinfo list for the site collection. You can use the below to list out users. You could then use the user item reference to delete the entry.

$web = get-spweb "<URL>"
$list = $web.Lists["User Information List"]
$users = $list.Items