SharePoint Online X-UA-Compatibility changes between tenants

[Pedro Pablo Díaz Arguello]

Hello! I have some problems with distinct sites. The new seattle.master uses <SharePoint:IECompatibleMetaTag> to define the IE version for the SharePoint site. But I have some tenants where it renders compatibility to IE10, and some others renders edge. Why is that? I'd like to force all tenants to go edge so my webpart works fine.

I uploaded a couple pictures: same site template, different tenants, different document mode :(

[#2]

How are you creating these custom WebParts?

[#3]

SPFX + React. There is a couple problems with Office UI React and IE10. But we didn't notice until some legacy pcs started accesing with IE. And it worked in a tenant, so it's harder to explain why it isn't working for just those clients.

I'll probably modify seattle.master to force the edge tag, but I know that ain't no good.