Heart of Gold lvl 3 - Sappers spawning at a alarmingly fast rate

During my stream today I noticed that sappers seem to spawn at a alarming rate, they become a uncontrollable swarm of death that no only requires quite a bit of cheese to deal with but also slows the FPS to a slideshow. I've attached a twitch clip for reference.

https://www.twitch.tv/mirana_equinox/clip/GiftedHelpfulArugulaTBTacoRight-KHMPffCbspIlArOy

as far as I can tell there seems to be no limit on how fast the sappers can respawn and also there seems to be no unit cap on sappers either to prevent this. further the game seems to throw level 10 hero waves at you almost instantly, I don't know if this is intentional but I've got a feeling they scale with the amount of sappers killed, which ofc is in the hundreds with this happening