I don't think i have been able to breed the last 2 or 3 tales dragons and it's been even longer on leaderboard ones. Very frustrating especially since it impacts earning the pieces to craft the monthly dragon.
While you need time to investigate the breeding issue i think you could very quickly decrease that monthly requirement from 25,000 down to maybe 20,000 which might be more attainable if a player cannot go past chapter 5 in 1 or both tales this month.
Another, i think, quick option is put the tales dragon on sale for coins!!
Also, i play bingo and it is a very very rare occurrence to have breed a dragon goals that utilize the colors needed for the tales or leaderboard. This bingo the closest breeds require birthstone, disco, breed white and yellow...all of which add terrible and long extra colors.
I have rented the breeding roost to help but so far with 20 tries, no tales dragon but too many socials and rainbows.