Matlab upgraded to HDF5 1.8.12 in R2015a. Matlab R2020a still uses HDF5 1.8.12. Newer versions of the HDF5 library can write HDF5 1.8 files when specific options are used (including from Python h5py). HDF5 1.8.12 was released in November 2013 so it would be nice if Matlab would upgrade their HDF5 library verson.
Check Matlab HDF5 version
[major,minor,rel] = H5.get_libversion()