(Sea content) Sailors lvl 10 stats reset to lvl1, while level 9 get extra stats

Bug Name:

(Sea content) Sailors lvl 10 stats reset to lvl1, while level 9 get extra stats​

Bug Description:

Continuation of http://forum.gameznetwork.com/threads/sea-content-sailors-get-no-stats-at-level-10.233514/
After v.2886 patch my previously level 10 sailors with normal (or below average) stats now have base level 1 stats, regardless of type (Innocent/Ambitious).
Screenshot > https://ibb.co/NC5r96g
What makes things weirder, is that existing level 9 sailors got their stats boosted significantly, but seems not by the same amount as lvl 9 stats + lvl 1 stats as Kolka mentioned in the previous bug report, that stats stack on hiring+leveling.
Screenshot > https://ibb.co/ygB6XN6

Before patch this sailor had 3.4% speed, so it doesn't seem to add 1.2% base speed to his stat.
The issue is not visual, stats seem to apply exactly as shown on sailors page, though top speed of ship doesn't match what I had before patch - I'll explain below.​

How to reproduce/proof:

In this case it doesn't seem reproducible with new sailors however (I haven't leveled any new ones to lvl10 either), by level 8 they get normal stat rolls so far.
So it's quite possible it's the conversion from last version issue or something else.
I'm afraid to get my existing lvl 9 to 10 as you can understand, because I would lose 4.3% speed potentially and get 1.2%. Not a nice trade

P.S.: What also confuses me, before patch I had 158% speed valor carrack with lvl9-10 sailors, but after patch top speed dropped below to 154-155 even though bugged sailors visually have more stats. Now I'm barely reaching 159% with 2 fresh non-bugged sailors and 3 old "boosted" lvl 9 ones AND also new Chiro Sails +10 gear (Before patch only had blue prow +10 for speed boost)​