I actually think it’s one the worst thing about WK. Especially in later level, instead of turning old kanji into new radical, they keep decomposing complex kanji into many pieces and as a result the mnemonic are super convoluted and doesn’t work anymore.
Here are some examples I remember:
務 (level 21) → 霧 (level 47) but wk teach it as 雨 Rain+矛 Spear+夂 Winter+力 Power
徴 (level 26) → 懲 (level 43) but wk teach it as 彳 Loiter+ 山 Mountain+王 King+夂 Winter
解 (level 21) → 蟹 (level 50) but wk teach it as 角 Angle+刀 Sword+牛 Cow+虫 Insect
死 (level 6) → 葬 (level 37) but wk teach it as 艹 Flowers+歹 Yakuza+匕 Spoon+ 廾 Twenty
The last one is especially infuriating because 葬 means burial and clearly the death component 死 in the middle play a semantic role. Why even inventing a mnemonic with yakuza and spoon and whatnot when the meaning already scream at us…
And sometimes there is also some entire series of kanji containing the same subkanji (with often a similar onyomi) like for example :
利 → 莉 痢 梨
蒦 → 獲 穫 護
I think WK should introduce first 利 and 蒦 as radical.