Totally unprofessional and a complete joke. Will never use them on a production system again. Always angry if they are mentioned here like they are a legitimate choice...
I did not mention the former employer or any of their projects/clients by their names and did not include any images of those projects that were protected by any copyright that they held. It was screenshots of the website functionality after I had removed all original styling and revamped it myself (on my own time on my own machine using only publicly available HTML/CSS) from the ground up to anonymize it. All branding and images were removed and replaced. These revamps were never publicly released and were only used to create screenshots to display their functionality. They claimed copyright ownership of the images that I took, on my own computer, that had zero resemblance to their own software except for the workflows that they had. These were all public facing sites and there was no internal/proprietary workflow information being shown. The work being displayed was 100% my own creation during my employment, and I was not claiming any credit for work that wasn't done by me.
I did not bother disputing the fraudulent DMCA claim because my former employer that did it was extremely litigious and loved lawsuits and loved making them as long and expensive as possible to punish the people they were trying to bully into submission. The owner would frequently boast in the (open concept) office about all his lawsuits and how he was forcing people to comply to his demands with the threat of ruining them financially with lawsuits.
It did have an impact on my ability to find new employment, but I found employment anyway. I just made a PDF version of my website (well laid out) and send that with my cover letter.