Will an Antimagic Field on a target of a "Haste" spell trigger the wave of lethargy?

Question

Haste is an incredibly useful buff in this edition: +2 AC, doubled movement rate, advantage on Dex saving throws, and a "cunning action" like free action that can even be used to Attack. It's a martial class's best friend, but has an important Achilles heel at the end of its description:

When the spell ends, the target can't move or take actions until after its next turn, as a wave of lethargy sweeps over it. - PHB p250

My question is whether something that suppresses the spell counts as an instance when the spell ends. This is particularly relevant to the Antimagic Field:

Spells. Any active spell or other magical effect on a creature or an object in the sphere [field] is suppressed while the creature or object is in it.- PHB p214

This question occurred to me when I was considering the role of spellcasters in a battle with a Beholder. The Beholder's antimagic field will not allow spellcasters to cast spells, but a spellcaster could still maintain concentration on a buff that they had cast when they were not yet in the field (according to http://www.sageadvice.eu/2016/06/14/how-do-you-rule-concentration-in-an-antimagic-field/). But I wondered if the Beholder would be able to trigger the lethargy by including the target of the spell in the field, perhaps even doing so repeatedly. For example, if a Wizard cast Haste on a Fighter, and then the Fighter was targeted by the antimagic field, what would happen?

Does a concentration spell count as the spell "ending" only when the spell is no longer being concentrated on, or does it also count when a spell temporarily stops having an effect?

Answer 1

No.

The antimagic field suppresses all of the effects of the haste spell, but it doesn't end the spell. While a creature under the effects of haste is inside an antimagic field, none of the effects (positive or negative) of the spell apply, but the spell itself still exists and hasn't ended.

Similarly, if a haste spell does end while the affected creature is inside an antimagic field, then there will be no "wave of lethargy"; that is also an effect of the spell, and it is also suppressed.

Contrast the wording of antimagic shell (the spell whose effects define those of an antimagic field) with that of dispel magic (PHB p., 234, emphasis mine):

Choose one creature, object, or magical effect within range. Any spell of 3rd level or lower on the target ends.

Dispel magic explicitly ends spells; if antimagic field and similar effects also did so, they would explicitly say so.

Answer 2

Suppressed is not the same as the end of Spell

From the PHB, pp214 Antimagic Field:

While an effect is supressed, it doesn't function, but the time it spends suppressed counts against its duration.

The actual magic has not ended - it is purely the effects of the spell that are suppressed. This confirms that the spell is still ongoing.

Ways to end a concentration spell

The methods for ending a spell are found on page 203 of the PHB

• Casting another spell that requires concentration
• Taking Damage (and failing CON save)
• Being incapacitated or killed
• Choosing to stop the spell on your own
• Spell has been Counterspelled or Dispelled via Dispel Magic

Anti-Magic field is none of these - and as it states, it only suppresses the magic - it doesn't stop it. Should the field end, the magical effects return.

Additional Notes

• Should Haste end while in the field, the negative effects would also be masked (as they are a function of the spell, which is suppressed.)