大方廣佛華嚴經隨疏演義鈔 84.8

84.8

疏「三所學已窮」者，謂於其自乘所學之法名為深入，非謂深入甚深法性，故引《法華》，即三乘同入之法性耳。「三獸渡河」，已見八地。

Regarding the Commentary's "Third, having exhausted what was to be learned": this means that regarding the teachings studied in their own vehicle, they are said to have deeply entered; it does not mean they have deeply entered the profound dharmatā. Therefore, it cites the Lotus Sūtra, which refers to the dharmatā into which all three vehicles enter alike. "Three beasts crossing the river" has already appeared in the Eighth Stage.