I have had a video copyright claimed by a company, which I then submitted a counterclaim for and had the video reinstated. Since then I have had numerous claims from the same company and have had to make the exact same counterclaim to reinstate the video. With the verdict having been previously reached (that the video is not a violation of copyright law) is it legal for a company to make that same claim again?
No-ish, it is not. The relevant sticking point would be in their DMCA takedown notice, where they have to follow 17 USC 512(c)(3)(A) and include in their notice
(v) A statement that the complaining party has a good faith belief that use of the material in the manner complained of is not authorized by the copyright owner, its agent, or the law.
(vi) A statement that the information in the notification is accurate, and under penalty of perjury, that the complaining party is authorized to act on behalf of the owner of an exclusive right that is allegedly infringed.
The key here is having a "good faith belief". There is a credible scenario where a company A could file multiple notices for the actually same material B posted by the exact same person C, where the person has the right to post that material, and do so in good faith. If A was not able to locate evidence of the permission to C, then they would shift the burden of proof to C – "good faith belief" doesn't mean that they have to be right, just that they have to actually think they are. If C also uses the name D, A would not be able to determine that the work was licensed to D based on the fact (once they know that) that it is licensed to C.
DMCA abuse is not an permanently open escape hatch. 17 USC 512(4) states
Any person who knowingly materially misrepresents under this section—
(1) that material or activity is infringing, or
(2) that material or activity was removed or disabled by mistake or misidentification,
shall be liable for any damages, including costs and attorneys' fees, incurred by the alleged infringer, by any copyright owner or copyright owner's authorized licensee, or by a service provider, who is injured by such misrepresentation, as the result of the service provider relying upon such misrepresentation in removing or disabling access to the material or activity claimed to be infringing, or in replacing the removed material or ceasing to disable access to it.
See Automattic Inc. v. Steiner, 82 F. Supp. 3d 1011. The ruling judge found that "Defendant could not have reasonably believed that the Press Release he sent to Hotham was protected under copyright". The appeal court drew on precedent and dictionary to fill in gaps w.r.t. "good faith belief", that the person
should have known if it acted with reasonable care or diligence, or would have had no substantial doubt had it been acting in good faith, that it was making misrepresentations
In this case, the abuser was flagrantly abusing the takedown system, and there is some reason to believe that in the instant case, the abuser had actual knowledge of non-infringement.
Rossi v. Motion Picture Association of America provides an alternative outcome. In this case, Rossi operated a website that appeared (note the word appear) to offer free downloads of movies, and the rights-holder MCAA filed a takedown notice. In fact, it did not offer any such downloads, but MCAA's investigation stopped prematurely. This court held that "good faith belief" is subjective, so Rossi did not prevail. It is no doubt crucial that Rossi actually counted on his customers thinking that you could get actual downloads of protected material.
Whether or not a DMCA abuse suit would succeed would depend very much on the factual details of why the material is not infringing, and how easily the rights-holder could know that there was no infringement.