Nah, Vietnam has no territorial disputes with Thailand, it's in fact Cambodia who has territorial disputes with Vietnam (Phu Quoc island), this dispute is officially settled, but because Khmer Rouge sympathizers still roam Cambodia, sometimes troubles are created.Vietnam has territorial disputes with Thailand and Cambodia, and Laos has always been vigilant that Vietnam may annex it.
In order to balance Vietnam's influence, the three countries rely on China. China has also gained influence over ASEAN through them.
If China and Vietnam have good relations, the 3 countries will strengthen relations with Russia or USA.
But as long as moderates run Cambodia, all is fine.