1) Last supported chrome version by mcafee is 53.0.2785.116 (now latest chrome version is 55). What the ... ? Latest Chrome supported versions updated almost 3 months ago. It's ridiculous.
2) Am I the only one who is facing false blockings i chrome - e.g. URL is reported incorrectly (for example user is uploading a file to business system, but in other tab is youtube and DLP blocks the upload, because it wrongly detects that file has been tried to upload to youtube) ? (we are using latest supported 53.0.2785.116 version of Chrome)
1) Support has been suspended due to recent changes in the Chrome browser which prevents the DLPe plugin from functioning as intended. Additional support will be added in the future. It sounds like you are already familiar with the article, however, you can subscribe to the article if you have a registered account to be notified when the status changes:
2) This sounds more likely that you are dealing with an issue with the content being posted to a web request URL or potentially passing through an HTTP referrer. You can configure DLP to only look at the address bar if you wish in the client configuration policy for DLP. There will also be a brief explanation on the functionality there:
You can also confirm by looking at the incident manager which should give some additional information:
If this is legitimately triggering off of a different tab opened and you are using a supported version of Chrome then I would recommend opening a support case for investigation.