So my job this week. Another contractor installed 450 sf of Ditra heat over OSB subfloor with Unmodified mortar. Ran the cable and everything. The owner read the Schluter manual that was left in the room along with the unmodified mortar bag in the trash and called the Schluter Rep. I was asked to Tear it out and do the re-install by the flooring dealer, the work was well done, just used the wrong product. We tore it out and ground the residue and installed new ditra heat mat, and reinstalled the cable. Oh and guess the tile --- 8x36 rectified porcelain plank with 1/8 grout joint.
Will post picks when finished.
I guess the take away here is remember to use modified mortar on wood sub-floors when using Schluter Ditra products.