Select option appears selected in IE, but model has a null value

[silvl]

I'm submitting a ... (check one with "x")

[x ] bug report => search github for a similar issue or PR before submitting
[ ] feature request
[ ] support request

Current behavior
On IE, when a select field type is used, the first item in the list appears to be selected but the model does not have a value selected.

Expected behavior
To not show any selection when value not specified in the model

Minimal reproduction of the problem with instructions
This is reproducable using the formly examples provided on the web and running in IE.
https://formly.dev/examples/bootstrap-formly/select

What is the motivation / use case for changing the behavior?

Please tell us about your environment:
IE 11

• Angular version: Version used with example

• Browser: IE 11

• Language: [all | TypeScript X.X | ES6/7 | ES5]

• Node (for AoT issues): node --version =

[silvl]

As a workaround, if you provide a "placeholder", it will display the placeholder when nothing is selected.

[aitboudad]

related to angular/angular#10010

[aitboudad]

fixed in 5.2.0