The HTTP parameters in the AJAX request come to the server empty

The client part of my application makes an AJAX POST to the server (Grails 2.2.0) using JQuery 1.7.x. Domain where the request is made the same as the one where loaded JS code. It was found that a month is 30 anomalous customers to POST'and come on the server empty. JavaScript enabled on the client.

What could be the cause of these anomalies?

User-agents are very different:

Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0) Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; GTB7.5; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)

Mozilla/5.0 (Windows NT 5.1; rv:22.0) Gecko/20100101 Firefox/22.0

Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET4.0C; .NET4.0E)

Opera/9.80 (Series 60; Opera Mini/7.1.32448/30.3442; U; EN) Presto/2.8.119 Version/11.10
Grails 2.2.0 / JQuery 1.7.2
October 3rd 19 at 02:29
3 answers
October 3rd 19 at 02:31
So maybe it's clients pranksters? Or antivirus\firewall on their side? Or plug a thread?

And it will be possible to know these customers in the future and hang any debug code on them?
October 3rd 19 at 02:33
JavaScript enabled on the client.
that is, it's real people? But somehow bots like...
Think, live, as some then call in support. - mollie.Shanah commented on October 3rd 19 at 02:36
October 3rd 19 at 02:35
Maybe these clients have glitches with the Internet channel, and part of jquery or HTML code with same POST parameters just didn't progresivas? It would be logical to ask these callers about their connection to exclude this version.

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