John Williamson SINCLAIR - Is John Williamson a duplicate of his brothers son John?

I have been looking at this profile and it doesn't make any sense to me. This profile is set up as a child of William Sinclair, was listed as 1st Earl of Orkney (removed by me), a brother of Henry I Sinclair, and with a purported marriage to Ingeborg of Denmark.

What makes this profile strange:
- The public sources for William Sinclair states that he only had one son, Henry Sinclair who inherited the Earl of Orkney title, so this means that a brother John couldn't have been Earl as well, so the title is definitely wrong.
- There was a description that he was a hostage in Norway for his brother. This is not impossible, but it also appears that Henry II Sinclairs brother John was a hostage for him as well, which seems like an odd coincidence that both Henry's have a brother John that was a hostage for them.
- The profile for Ingeborg makes no mention of any John Williamson other than them being linked as married, but if you look at the other details this doesn't make sense. William was supposedly born in 1350, while Ingeborg was born in 1347 and died in 1370 aged 23. While the ages then matches, Ingeborg had been promised to Heinrich III of Mechlenburg since she was 3 years old (in 1350), they got married in 1362 (when she was 15), and as he didn't die until 1383 she was never a widow and able to remarry, so this link has to be wrong as well. Interestingly the wikipedia page for Henry I states that it was his son John who purportedly was married to Ingeborg, which is even more impossible as John (Henrysson) was born around 1375.

What do we then know about the supposed John Williamson? We have an uncertain birth and an uncertain death, a possible claim that he was a hostage in Norway, plus a claim that he was killed in battle against the English on Orkney, likely then at the 1401 invasion, but without any sources for any of this.
This leaves the open question: Was there ever a John Williamson and does anyone have any sources for him having existed, or is this profile just a duplicate of Henry I's son John (1376-1420) so that these profiles should be merged?