The paragraph originally comes from a book by Rev. William Ward, A View of the History, Literature, and Mythology, of the Hindoos, second edition, volume 1, p. 228 (Serampore: Mission Press, 1818). This fact indicates the early and tentative nature of this information. One of the leading Sāṃkhya-Yoga scholars of our time, the late Ram Shankar Bhattacharya, wrote a brief article in which he reported his meager findings about Patañjali in the purāṇa literature: "Patanjali, The Author of the Yogasutra," (Journal of the Yoga Institute, Santa Cruz, India, vol. 27, no. 1, August 1981, pp. 178-180). He makes no mention of the things found in the above-quoted paragraph. (Of course, the Rudra-yāmala is a tantra rather than a purāṇa.)

This paragraph entered William Judge's book in the following way. In 1889, when Judge's book was published, there were only two complete English translations of the Yoga-sutra. James Ballantyne had translated the first two of its four books, published at Allahabad in 1852 and 1853. Govindadeva Sastri translated the last two of its four books, published in The Pandit, 1868-1872. Tookaram Tatya then gathered these together and published them for the Bombay Branch of the Theosophical Society in The Yoga Philosophy, 1882, with a 2nd revised edition in 1885. I have not seen the 1st ed., but the 2nd ed. has an Introduction by Col. Olcott in which he writes, p. ii:

"A short sketch of the life of Patanjali is reproduced from 'A View of the History, Literature, and Mythology of the Hindus,' by the late Rev. William Ward of Serampore."