Having the same problem with Barclay. Found this link
Reviewed my latest statement and sure enough, only one transaction from each posting date is being imported. Although the link above references this starting in April, the issues seems to go back farther than that.
EDIT: My first missing transaction is from Jan 31.
Update - I called BarclayCard today and the customer service rep knew immediately about my problem and transferred me to Tech support, "Chris" in India. After the runaround about whether I had contacted Quicken he acknowledged awareness of the problem being with Barclay but said he had no information about what Barclay was doing to resolve it.
This sure feels like an issue at Barclay's end.
Download your transactions from a certain date to today's date as a Quicken file. Open the downloaded .qfx file with a Text Editor. In the transaction there is a section called <FITID>00004000021170425. You can update this number to be unique. What I did was just change the first 2 digits to 01, 02, 03, etc. to maintain some sequence. Save the file and then Import it in Quicken. You should see all the transactions there.
Hope it works for all of you! Enjoy, Deepak
Annoying that this happened and took so long to resolve...but glad that it's hopefully solved for good.