Sat 29th May 2021: It looks as if there was a weak opening from Europe to Australia on the 50 MHz with a few weak FT8 signals making it through.
Txmtr Rcvr Band Mode Distance Time (UTC)
DF5VAE VK4HJ 6m FT8 15477 km 06:05:29
UT7UV VK4HJ 6m FT8 14545 km 04:18:44
SP3MM VK4CZ 6m FT8 15564 km 07:10:14
VK4CZ UT2XQ 6m FT8 14683 km 06:59:59
SP4K VK3OER 6m FT8 15383 km 05:17:41
It looks as if there was a successful FT8 contact between VK4CZ in Australia and SP3MM in Poland, a distance of about 15564kms. The signals seem to have been quiet weak and were in the range of -16dB to -20dB which is below what is audible to the human ear i.e. a cw contact would not have been possible.
As for the propagation mode, it seems likely it was multi-hop Sporadic-E with possibly eight hops required. I say 'likely' as I sometimes wonder what are the chances of getting eight Sp-E hops in a row at 50 MHz.
We still have all of June to go yet so there could be more openings on 50 MHz from Europe to Australia.