"And has not this testimony been fulfilled in every particular? The First-day Adventists have set time after time, and notwithstanding the repeated failures, they have gathered courage to set new times. God has not led them in this. Many of them have rejected the true prophetic time, and ignored the fulfillment of prophecy, because the time passed in 1844, and did not bring the expected event. They rejected the truth, and the enemy has had power to bring strong delusions upon them that they should believe a lie. The great test on time was in 1843 and 1844; and all who have set time since then have been deceiving themselves and deceiving others. 1T 73.1 Up to the time of my first vision I could not write; my trembling hand was unable to hold my pen steadily. While in vision, I was commanded by an angel to write the vision. I obeyed, and wrote readily. My nerves were strengthened, and my hand became steady. 1T 73.2"
"And for this cause God shall send them strong delusion, that they should believe a lie:"
The EGW passage directly uses the concept of 'strong delusion' and 'believe a lie' in the same context as 2 Thessalonians 2:11, indicating a clear allusion.