Issues with refreshing report, random, loading data but not analyzing

We have an issue that happens randomly and makes our reports lose credibility in front of our customers.
We created an Angular application using the template on the web site. Our reports are feeding from web services, with csv data.
When loading a new json configuration file, that describes a new URL for the web service and the corresponding pivot configuration, we execute this.pivot1.flexmonster.setReport(this.currentReport). If we just change some params that the web service uses, to produce different data, we execute this.pivot1.flexmonster.updateData(this.currentDataSource).
Everything works as planned, only that, randomly, we see the "Loading data" and then, immediately, the report on the screen refreshes and shows incomplete data. Normally, the "Loading data" message is followed by "Analyzing data", and that takes a while. When we have the issue, though, we don't see that analyzing data message.
Most of the times we refresh again and everything looks fine. You realize, though, that the users are getting annoyed with the behavior, and keep telling they cannot trust the report results.
We tried to debug, got Fiddler as a proxy, thinking there is an issue with the web service/data. We then saw the data, though, was complete, and identical, between the one time it didn't work, and the time it worked.
My conclusion was that there is something going on with FlexMonster, specific or not to the browser. Saw that the issue was less frequent in Internet Explorer 11, but it happened on all Chrome based browsers, Chrome, Opera, new Microsoft Edge Beta. We didn't see the issue in Mozilla, but that could be we just didn't hit the context for the error.
When the refresh issue happens, there is NO console error message.
What is most frustrating is that we cannot reproduce the context so we can only assume things.
We saw a similar issue in another post here, and the answer was a work-around, forcing FlexMonster to redraw from scratch, by setting to null, but that didn't work, or we didn't know how to do it correctly.
Between changing configs, we execute

this.pivot1.flexmonster.clear();
this.pivot1.flexmonster.setReport({});
 
The issue DOESN'T happen immediately after the cleanup below, necessarily. It can happen sometimes on setReport, sometimes on updateData.

 
Can you give us a hint if anyone else signaled this issue, or if there is a workaround?
We have a full license, and we use version 2.7.6, very recent.
 
Thank you in advance.