depends on how your laptops power charge control works, it varies between manufacturers. generally any battery that is below 40% will make the charger switch into 'balance mode' which is a special charging state to ensure your battery cells all charge uniformly (prevents explosions / something sony got wrong on a laptop once, if you recall the news).
it maybe impossible for you to 'fix' this habit your laptop has. especially if you have a gpu in it, the laptop maybe limiting the gpu performance to allow the power to charge the battery to a 'safe' limit as any major draining will interfere with the balancing.
secondly, constantly charging your battery is better than draining below 30% ! your battery has a recharge life of around 1000 full recharges (to retain 80% of its capacity) ... every time you deep discharge (run below 30%) it shortens this count ... to as little as 250 charges ... that means if you deep discharge every day, your battery life will shorten to 80% in less than a year. BUT recharing your battery above 90% extends this count to around 1500 'full' recharges* so infact, having it plugged in all the time will make the battery last a lot longer than many believe.
finally, the reason people think that removing the battery is best: it is. battery discharge takes a few months when its removed from laptop. 1000 full recharges at monthly intervals .... decades of life. longer than your fingers will last. - this is an unrealistic target, as your laptop will probably die from heat cycles long before this.
*90% - 100% is 10% ... thers 10 x 10% in a full charge ... 1500 recharges x 10 = 15000 recharges from 90% to full before battery suffers capacity loss.