How to avoid Table Lock Escalation?

I've got a task to update 5 million rows in a production table, without locking down the whole table for extended time So, I used approach that helped me before many times - updating top (N) rows at a time with 1-N second interval between chunks This time started with update top (1000) rows at a time, monitoring the Extended Events session for lock_escalation events in the process lock_escalation showed up during each update operation, so I started lowering row count per chunk 1000 -> 500 -> 200 -> 100 -> 50 rows and so on down to 1 Before (not with this table, and for delete operations - not update), lowering row count to 200 or 100, helped to get rid of lock_escalation events But this time, even with 1 row per 1 update operation, table lock_escalation still shows up. Duration of each update operation is about the same, regardless if its 1 row or 1000 rows at a time How to get rid of table lock escalations in my case ? @@TRANCOUNT is zero Extended event: Code :

set nocount on

declare 
	@ChunkSize				int = 1000,							-- count rows to remove in 1 chunk 
	@TimeBetweenChunks		char(8) = '00:00:01', 				-- interval between chunks
	
	@Start					datetime,
	@End					datetime,
	@Diff					int,
	
	@MessageText			varchar(500),
	
	@counter				int = 1,
	@RowCount				int = 1,
	@TotalRowsToUpdate		bigint,
	@TotalRowsLeft			bigint
	


-- total row count to update
set @TotalRowsToUpdate = (select count(*)
							from [Table1]
								join [Table2] on
									btid = tBtID
							where	btStatusID = 81)


set @TotalRowsLeft = @TotalRowsToUpdate
set @MessageText = 'Total Rows to Update = ' + cast(@TotalRowsLeft as varchar) raiserror (@MessageText,0,1) with nowait
print ''



-- begin cycle
while @RowCount > 0 begin

	set @Start = getdate()

	-- update packages
	update top (@ChunkSize) bti
		set	btstatusid = 154,
			btType = 1
	from [Table1] bti
		join [Table2] on
			btid = tBtID
	where	btStatusID = 81
	

	set @RowCount = @@ROWCOUNT

	-- measure time
	set @End = getdate()
	set @Diff = datediff(ms,@Start,@End)

	set @TotalRowsLeft = @TotalRowsLeft - @RowCount
	set @MessageText = cast(@counter as varchar) + ' - Updated ' + cast(@RowCount as varchar) + ' rows in ' + cast(@Diff as varchar) + ' milliseconds - total ' + cast(@TotalRowsLeft as varchar) + ' rows left...'

	-- print progress message
	raiserror (@MessageText,0,1) with nowait


	set @counter += 1

	WAITFOR DELAY @TimeBetweenChunks

end

Plan: https://www.brentozar.com/pastetheplan/?id=SyozGWMLw