Mysterious precipitate in reaction of copper sulfate and calcium hypochlorite
The creation reaction for copper hypochlorite per Mellor:
$$
CuSO4+Ca(OCl)2 → CaSO4(s)+Cu(OCl)2
$$
However, copper hypochlorite is not stable and on standing breaks down. I believe Mellor is likely accurate on describing the reaction and products:

Reference: "A comprehensive treatise on inorganic and theoretical chemistry", Volume 2, by Joseph William Mellor, page 271. To quote:

"R. Chenevix notes the ready solubility of cupric oxide in chlorine water, and P. Grouvelle found that the soln. obtained by passing chlorine into water with cupric oxide in suspension possessed bleaching properties, and these were retained even after the soln. had been boiled for a quarter of an hour. A. J. Balard found that the distillation of P. Grouvelle's liquor furnished some hypochlorous acid and a green oxychloride, 3CuO.CuCl2.4H20, was formed in the retort. A. J. Balard prepared a soln. of cupric hypochlorite by dissolving cupric hydroxide in hypochlorous acid. It is also made by the action of cupric sulphate on calcium hypochlorite. A. J. Balard found that copper filings are partially dissolved by hypochlorous acid, the soln. after standing some time contains cupric chloride, and deposits a green pulverulent cupric oxychloride."

Link: https://books.google.com/books?pg=PA271&amp;lpg=PA271&amp;dq=zinc+hypochlorite&amp;id=7XoGAQAAIAAJ&amp;ots=R0byHnamKL#v=onepage&amp;q=zinc%20hypochlorite&amp;f=false 

So, the cupric oxychloride product maybe mixed with CaSO4.

Note, Copper oxychloride, per Wikipedia, is now referred to as dicopper chloride trihydroxide with the formula Cu2(OH)3Cl (or, more informatively, I would write as Cu(OH)2Cu(OH)Cl).

[I have personally prepared dibasic magnesium hypochlorite on another forum by mixing MgSO4 with NaOCl (aq) and adding NaOH. A white precipitate of dibasic magnesium hypochlorite results (which I have collected and experimented with). It is also NOT Mg(OH)2. Link: https://www.sciencemadness.org/whisper/viewthread.php?tid=26741#pid303723 There is also the reputed compound 'copper carbonate' which actually is also always basic copper carbonate per Wikipedia https://en.wikipedia.org/wiki/Basic_copper_carbonate ].