Unable to get webLink for Microsoft 365 Group messages using Microsoft Graph

If a user is added to a Microsoft 365 group, they receive new mails in their inbox,

but previous mails remain inside the group mailbox (visible in Outlook under Groups).

I want to search a work order number in both:

1. The user's inbox

2. The group conversations (previous group mails)

To search inside the user's inbox, I used:

GET https://graph.microsoft.com/v1.0/me/messages?$search="{workOrder}"&$select=subject,bodyPreview,webLink,from,receivedDateTime

To search inside the groups, I used:

GET https://graph.microsoft.com/v1.0/groups/{groupId}/threads?$expand=posts($select=id,body,receivedDateTime,from)&$select=id,topic,lastDeliveredDateTime&$top=50

The issue is that group messages don’t include a `webLink` property.

I also tried manually constructing a webLink like this:

https://outlook.office365.com/mail/group/{groupId}/conversations/{conversationThreadId}

But this only redirects to Outlook and not to the specific message.

Is there any way to get the `webLink` (or a similar URL) for group mails using Microsoft Graph?

These are the scopes I’m currently using:

Mail.Read

Mail.ReadWrite

Mail.Send

User.Read

Mail.Read.Shared

Group.Read.All

ChannelMessage.Read.All

Team.ReadBasic.All

Channel.ReadBasic.All

offline_access