Burned vs. Burnt, and other verbs like this

Only American English makes a distinction between the two. In other varieties of English, burnt and burned are both perfectly acceptable for the past tense of burn. It wasn’t always that way. Before the sixteenth century, burned was the only form. However, some people started adding T instead of -ed at the ends of verbs. The fad caught on a little in the United States and Canada, but not enough to become an established part of the language there. In the United Kingdom and other countries, the T was a hit. Here are some examples of burnt functioning as the simple past tense and past participle of burn...

(From Grammarly)

Others verbs following a similar pattern

	Clap	Clapped Clapt	Clapped Clapt
31	Dream	Dreamt Dreamed	Dreamt Dreamed
	Kneel	Knelt Kneeled	Knelt Kneeled
	Lean	Leant Leaned	Leant Leaned
	Leap	Leapt Leaped	Leapt Leaped
45	Learn	Learnt Learned	Learnt Learned
61	Smell	Smelt Smelled	Smelt Smelled
	Spell	Spelt Spelled	Spelt Spelled
63	Spill	Spilt Spilled	Spilt Spilled
	Spoil	Spoilt Spoiled	Spoilt Spoiled
	Strip	Stript Stripped	Stript Stripped
	Sunburn	Sunburned Sunburnt	Sunburned Sunburnt
69	Sweep	Swept Sweeped	Swept Sweeped
	Vex	Vext Vexed	Vext Vexed

From usingEnglish.com