I have used two methods to create views: one through the Portal UI and one through the API.
In the former, I use the Create View button on the hosted feature layer item page. This replaces the space characters (HTML encoded %20) in my view title with underscores.
For example, it generates the REST URL:
In the latter, I use the FeatureLayerCollection Manager method create_view(name="Hosted Feature Layer View Name"). This time it replaces the space characters with the HTML-encoded value
For example:
https://services.arcgis.com/.../arcgis/rest/services/Hosted%20Feature%20Layer%20View%20Title/FeatureServer/9
I found this to be an issue, because I overwrite a hosted feature layer, which requires me to drop my views and then recreate them after overwriting. I have web maps with layers depending on these views that break when that URL changes (between spaces or underscores).
I was able to fix the URL by opening the content JSON of the web map.
As I build out our management tools using the API, we will eventually settle on the API method to creating views. But as we are developing and multiple people are touching these hosted layers, this can cause issues.