Due to the multi-year delays of the 10nm node, Intel landed itself in trouble last year as most of the company's product portfolio was on 14nm and the company did not have sufficient 14nm production capacity to meet all demand. The shortages eased this year and the chip giant invested a lot of money to expand production, but it appears this is still not enough to meet this year's holiday season demand.
The first 10nm "Ice Lake" processors are in production right now but it's believed it will still take some time until these products ship in high volume. It's unknown if there's also a shortage of 14nm desktop CPUs.